JP5046743B2 - Solar cell module and manufacturing method thereof - Google Patents

Description

  The present invention relates to a solar cell module including a plurality of solar cells connected to each other by a wiring material between a front surface side protective material and a back surface side protective material, and a manufacturing method thereof.

  Solar cells are expected as new energy sources because they directly convert clean and inexhaustible sunlight into electricity.

  The output per solar cell is about several watts. Therefore, when a solar cell is used as a power source for a house or a building, a solar cell module in which a plurality of solar cells electrically connected by a wiring material are sealed with a sealing material is used.

  In general, a plurality of thin wire electrodes for collecting carriers and a bus bar electrode for collecting carriers from the thin wire electrodes are formed on the solar cell substrate.

The wiring material is formed by coating a solder layer on the outer periphery of a copper foil or the like. The wiring member is thermally bonded to the bus bar electrode of one solar cell and the bus bar electrode of another solar cell adjacent to the one solar cell. Specifically, the wiring member is firmly bonded to the bus bar electrode via a solder alloy layer formed at the interface between the solder layer of the wiring member and the bus bar electrode (for example, Patent Document 1).
JP 2002-359388 A (page 3, FIG. 1)

  On the other hand, it has been proposed by the present applicant to reduce the manufacturing cost by joining the wiring material to the thin wire electrode via a resin adhesive without forming the bus bar electrode (Japanese Patent Application No. 2006-229209). When the wiring material is directly bonded to the fine wire electrode in this way, the amount of the fine wire electrode embedded in the solder layer of the wiring material affects the adhesive force between the wiring material and the solar cell. That is, the greater the amount of thin wire electrode embedded, the better the adhesion between the wiring material and the solar cell.

  Here, since the sealing material for sealing the solar cell repeats expansion and contraction due to temperature changes in the usage environment, stress is generated at the interface between the thin wire electrode and the sealing material. In order to reduce the influence of such stress, the thin wire electrode is preferably formed using a material as soft as possible.

  However, when the fine wire electrode is formed using a soft material, the fine wire electrode is crushed by the pressure when joining the wiring material, and the amount of embedding in the wiring material is reduced. Thus, there was room for improvement in improving the adhesion between the wiring material and the solar cell.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a solar cell module in which the adhesive force between the wiring material and the solar cell is strengthened and the reliability is improved.

  The solar cell module according to the first aspect of the present invention includes a plurality of solar cells connected to each other by a wiring material between a front surface side protective material, a back surface side protective material, and the front surface side protective material and the back surface side protective material. A solar cell module including a battery, wherein the solar cell includes a substrate and a thin wire electrode formed in a line shape on a surface of the substrate, and the thin wire electrode is bonded to the wiring member. A first portion and a second portion that is not bonded to the wiring member, wherein the hardness of the first portion is greater than the hardness of the second portion, and the first portion is embedded in the wiring member; The gist of this is

  In the solar cell module according to the first feature of the present invention, the wiring member has a low resistance layer and a conductor layer formed on an outer periphery of the low resistance layer, and the first portion includes It is preferably embedded in the conductor layer.

  In the solar cell module according to the first aspect of the present invention, the conductor layer is formed of solder, the wiring member is bonded to the substrate via a resin adhesive, and the curing temperature of the resin adhesive is Is preferably lower than the melting temperature of the solder.

  The method for manufacturing a solar cell module according to the second feature of the present invention is a method for manufacturing a solar cell module comprising a plurality of solar cells connected to each other by joining a wiring material to a line-shaped thin wire electrode, Among the thin wire electrodes, a step A for forming a first portion joined to the wiring member in a line shape, a step B for curing the first portion by heating the first portion, and the thin wire electrode Forming a second portion that is not bonded to the wiring material in a line; and heating the first portion and the second portion to cure the first portion and the second portion; and A step E of joining the wiring member to the first portion while heating the wiring member, wherein the hardness of the first portion is larger than the hardness of the wiring member in the step E. To do.

  The method for manufacturing a solar cell module according to the third aspect of the present invention is a method for manufacturing a solar cell module comprising a plurality of solar cells connected to each other by joining a wiring material to a line-shaped thin wire electrode, A step A of forming a first portion joined to the wiring member of the fine wire electrode in a line shape, a step B of forming a second portion of the fine wire electrode not joined to the wiring material in a line shape, and the first A process C for curing the first part and the second part by heating one part and the second part, and a process D for joining the wiring material to the first part while heating the wiring material. The hardness of the material used for the first part is larger than the hardness of the material used for the second part. In the step D, the hardness of the first part is higher than the hardness of the wiring material. large The gist of the door.

  ADVANTAGE OF THE INVENTION According to this invention, the adhesive force of tab wiring and a solar cell can be strengthened, and the solar cell and solar cell module which improved reliability, and its manufacturing method 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.

1. First Embodiment (Configuration of Solar Cell Module)
The solar cell module according to the first embodiment will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing the configuration of the solar cell module according to this embodiment. As shown in the figure, the solar cell module 1 according to this embodiment includes a plurality of solar cells 10, a tab wiring 40, a sealing material 50, a front surface side protective material 60 and a back surface side protective material 70.

  The solar cell 10 according to the present embodiment includes a photoelectric conversion unit 20, a light receiving surface side thin wire electrode 30, and a back surface side thin wire electrode 31.

  The photoelectric conversion unit 20 sandwiches a substantially intrinsic amorphous silicon layer between the single crystal silicon substrate and the amorphous silicon layer, reduces defects at the interface, and improves the characteristics of the heterojunction interface. It is a solar cell substrate having a structure, a so-called HIT structure. Note that the photoelectric conversion unit 20 may be a solar cell substrate based on a crystalline semiconductor substrate such as a single crystal silicon substrate or a polycrystalline silicon substrate.

  FIG. 2 is a plan view of the solar cell 10 according to the present embodiment. As shown in the figure, on the light receiving surface side surface (hereinafter referred to as “light receiving surface”) of the photoelectric conversion unit 20, the light receiving surface side thin wire electrode 30 is formed in a line shape. A large number of the light receiving surface side thin wire electrodes 30 are formed substantially in parallel over substantially the entire area of the light receiving surface. For example, about 100 light receiving surface side thin wire electrodes 30 are formed with a width of about 0.1 mm.

  As shown in FIG. 1, on the back side surface (hereinafter referred to as “back side”) provided on the opposite side of the light receiving surface of the photoelectric conversion unit 20, the back side thin wire electrode 31 is formed in a line shape. . A large number of back surface side thin wire electrodes 31 are formed substantially parallel over substantially the entire back surface. Since it is not necessary to consider the reduction of the light receiving area on the back surface side of the solar cell 10, more fine wire electrodes than the light receiving surface side fine wire electrode 30 can be formed, and electrical resistance loss can be reduced.

  The light receiving surface side thin wire electrode 30 and the back surface side thin wire electrode 31 according to the present embodiment are formed by thermosetting a thermosetting conductive paste. The thermosetting conductive paste is a resin paste using a thermosetting resin as a binder. As the thermosetting conductive paste, for example, a silver paste in which silver particles are dispersed in an epoxy thermosetting resin solution is used.

  As shown in FIG. 2, the tab wiring 40 is joined to the light receiving surface of one solar cell 10 and the back surface of another solar cell 10 adjacent to the one solar cell 10.

  FIG. 3 is an enlarged view of a portion A in FIG. As shown in the figure, the light-receiving surface side thin wire electrode 30 is formed on the first portion 30a formed on the region where the tab wiring 40 is joined and on the region where the tab wiring 40 is not joined, and the first portion 30a. And a second portion 30b. The hardness of the first portion 30a is greater than the hardness of the second portion 30b. A resin adhesive 80 is disposed in a region where the tab wiring 40 is joined.

  4 is a cross-sectional view taken along the line BB in FIG. As shown in the figure, a first portion 30 a and a second portion 30 b are formed on the photoelectric conversion unit 20 so as to be continuous. Tab wiring 40 is joined to the first portion 30a. The tab wiring 40 includes a low resistance body 41a such as a copper foil and a conductor 41b plated on the outer periphery of the low resistance body 41a. In the present embodiment, solder (mainly tin) is used as the material of the conductor 41b constituting the tab wiring 40. As the material of the conductor 41b, a material that is softer than the first portion 30a at the temperature at which the tab wiring 40 is bonded, that is, the temperature at which the resin adhesive 80 is cured is used. For example, a soft conductive metal such as eutectic solder with a lowered melting point can be used for the conductor 41b.

  5 is a cross-sectional view taken along the line CC of FIG. As shown in the figure, the first portion 30 a is embedded in the tab wiring 40. Specifically, it is embedded in the conductor 41 b included in the tab wiring 40. Thereby, the 1st part 30a and the tab wiring 40 are connected mechanically and electrically.

  Further, the first portion 30a may be embedded to a depth reaching the low resistance body 41a when embedded in the conductor 41b. If the width and thickness of the tab wiring 40 are determined in consideration of the rigidity and resistance value of the tab wiring determined by the combination of the low resistance body 41a and the conductor 41b, the yield and characteristics can be improved. Good.

  As shown in FIG. 5, the tab wiring 40 is bonded to the photoelectric conversion unit 20 via a resin adhesive 80. As the resin adhesive 80, a strip-shaped film sheet mainly composed of an epoxy resin can be used. The resin adhesive 80 is blended with a crosslinking accelerator so that the crosslinking is rapidly accelerated by heating at about a few tens of degrees and the curing is completed in about several tens of seconds. The width of the resin adhesive 80 is preferably equal to that of the tab wiring 40 in consideration of shielding of incident light.

  The resin adhesive 80 has been described as having an epoxy resin as a main component. However, it can be bonded at a temperature lower than that of solder bonding, preferably 200 ° C. or less, and about 20 seconds so as not to significantly impair productivity. As long as curing is complete. 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.

  Further, the resin adhesive 80 may contain fine particles. The fine particles have an average particle size of about 10 μm, and nickel, gold-coated nickel, or plastic mixed with particles coated with a conductive metal such as gold can also be used.

  The configuration on the light receiving surface side of the photoelectric conversion unit 20 has been described above, but the same configuration may be provided on the back surface side. That is, the first portion 30 a of the back surface side thin wire electrode 30 may be embedded in the tab wiring 40, and the tab wiring 40 and the back surface of the photoelectric conversion unit 20 may be joined by the resin adhesive 80.

(Method for manufacturing solar cell module)
Next, the manufacturing method of the solar cell module 1 according to the present embodiment will be described with reference to the drawings.

  First, the photoelectric conversion part 20 as a solar cell substrate as shown in FIG. 6 is produced. FIG. 6A is a cross-sectional view of the photoelectric conversion unit 20. An RF plasma CVD method is used to sequentially form an i-type amorphous silicon layer 20c and a p-type amorphous silicon layer 20b on the light receiving surface side of the n-type single crystal silicon substrate 20d. Similarly, an i-type amorphous silicon layer 20e and an n-type amorphous silicon layer 20f are sequentially formed on the back side of the n-type single crystal silicon substrate 20d. Next, an ITO film 20a is formed on the light receiving surface side of the p-type amorphous silicon layer 20b by using a magnetron sputtering method. Similarly, an ITO film 20g is formed on the back side of the n-type amorphous silicon layer 20f.

  FIG. 6B is a plan view of the photoelectric conversion unit 20. As shown in the figure, the light receiving surface of the photoelectric conversion unit 20 has a first region α where the tab wiring 40 is joined and a second region β where the tab wiring 40 is not joined. The width of the first region α does not have to be the same as the width of the tab wiring 40, and may be set to be somewhat larger than the width of the tab wiring 40. Note that the back surface of the photoelectric conversion unit 20 also includes the first region α and the second region β.

  Next, as shown in FIG. 7A, the first portion 30 a of the light receiving surface side thin wire electrode 30 joined to the tab wiring 40 is formed on the first region α on the light receiving surface side of the photoelectric conversion unit 20. . In the present embodiment, a plurality of first portions 30 a are formed along a direction substantially orthogonal to the longitudinal direction of the tab wiring 40. Similarly, the 1st part 31a (not shown) of the back surface side thin wire electrode 31 is formed on the 1st area | region (alpha) of the back surface side of the photoelectric conversion part 20. As shown in FIG.

  Specifically, a silver paste is screen-printed on the first region α on the light receiving surface side, and after the silver paste is temporarily cured by heating at a temperature of several hundred degrees for several minutes, the first region on the back surface side A silver paste is screen-printed on α, and the silver paste is temporarily cured by heating at a temperature of a few hundred degrees for several minutes. Thereafter, the first portions 30a and 31a are cured by heating the silver paste on both sides for about 30 minutes at a temperature of a few hundred degrees.

  Next, as illustrated in FIG. 7B, the second portion 30 b of the light receiving surface side thin wire electrode 30 that is not joined to the tab wiring 40 is formed on the second region β on the light receiving surface side of the photoelectric conversion unit 20. In the present embodiment, a plurality of second portions 30b are formed so as to continue to the first portion 30a along a direction substantially orthogonal to the longitudinal direction of the tab wiring 40. Similarly, a second portion 31 b (not shown) of the back surface side thin wire electrode 31 is formed on the second region β on the back surface side of the photoelectric conversion unit 20.

  Specifically, a silver paste is screen-printed on the second region β on the light receiving surface side, and after the silver paste is temporarily cured by heating at a temperature of several hundred degrees for several minutes, the second region on the back surface side A silver paste is screen-printed on β, and the silver paste is temporarily cured by heating at a temperature of a few hundred degrees for several minutes. Thereafter, the second portions 30b and 31b are cured by heating the silver paste on both sides for about 30 minutes at a temperature of a few hundred degrees, and the first portions 30a and 31a are completely cured. In the present embodiment, the silver paste material having the same composition can be used for the silver paste of the first portions 30a and 31a and the second portions 30b and 31b.

  As described above, the light receiving surface side thin wire electrode 30 and the back surface side thin wire electrode 31 are formed on the light receiving surface and the back surface of the photoelectric conversion unit 20. Since the first portions 30a and 31a are heated for a longer time than the second portions 30b and 31b, the hardness of the first portions 30a and 31a is larger than the hardness of the second portions 30b and 31b.

  Next, a band-shaped film sheet (resin adhesive 80) containing epoxy resin as a main component is pasted on the first region α on the light receiving surface side and the back surface side. The tab wiring 40 is placed on the belt-shaped film sheet and lightly crimped.

  Next, heating is performed while pressing from the upper part of the tab wiring 40 toward the photoelectric conversion unit 20. Specifically, it is set in a device having a structure having a heater block heated up and down to a temperature of a few hundred degrees and having a function of keeping the applied pressure constant. With the upper and lower heater blocks, for example, the pressure is sandwiched between the pressures of 2 MPa, and the time required for curing the resin adhesive 80, for example, heating for about 15 seconds, is bonded.

  During this heating, the hardness of the first portions 30 a and 31 b is greater than the hardness of at least the conductor 41 b portion of the tab wiring 40. Accordingly, the first portions 30a and 31b are embedded in the conductor 41b. Thereby, the first portions 30a and 31b and the tab wiring 40 are mechanically and electrically connected.

  The conductor 41b (tin) formed on the outer periphery of the tab wiring 40 has about half the hardness of silver even at room temperature. The hardness of the conductor 41b is further reduced by heating to a temperature of a few hundred degrees. The tab wiring 40 disposed on the front and back surfaces of the solar cell 10 is uniformly pressurized with, for example, a pressure of 2 MPa, so that the first portion 30a fluidly removes the resin adhesive and the conductor of the tab wiring 40 It is easily embedded in 41b (tin).

  Next, the EVA sheet (sealing material 50), the plurality of solar cells 10 connected by the tab wiring 40, the EVA sheet (sealing material 50), and the back surface protection material on the glass substrate (light-receiving surface side protection material 60). 70 are sequentially laminated to obtain a laminated body.

  Next, the laminated body is temporarily pressure-bonded by thermocompression bonding in a vacuum atmosphere, and then the EVA is completely cured by heating under a predetermined condition.

  Thus, the solar cell module 1 is manufactured. Note that a terminal box, an Al frame, or the like can be attached to the solar cell module 1.

(Function and effect)
According to the configuration of the solar cell module according to the present embodiment, the light-receiving surface side thin wire electrode 30 includes the first portion 30a to which the tab wiring 40 is joined and the second portion 30b to which the tab wiring 40 is not joined, The hardness of the first portion 30a is greater than the hardness of the second portion 30b. That is, the hardness of the first portion 30 a joined to the tab wiring 40 is larger than the hardness of the second portion 30 b joined to the sealing material 50.

  Here, when the tab wiring 40 is directly joined to the first portion 30a, the adhesive strength between the tab wiring 40 and the solar cell 10 increases as the amount of the first portion 30a embedded in the tab wiring 40 increases. .

  Further, in the environment where the solar cell module is used, when light reception and non-light reception are repeated alternately, the sealing material 50 and the tab wiring 40 repeat expansion and contraction. Generally, since the linear expansion coefficient of the sealing material 50 is larger than the linear expansion coefficient of the tab wiring 40, the stress generated at the interface between the second portion 30b and the sealing material 50 is the first portion 30a and the tab. It is larger than the stress generated at the interface with the wiring 40. That is, in the usage environment of the solar cell module, damage is more easily accumulated in the second portion 30b than in the first portion 30a.

  In the configuration of the solar cell module according to the present embodiment, the first portion 30a is harder than the second portion 30b. Therefore, since the amount of the first portion 30a embedded in the tab wiring 40 can be increased, the adhesive force between the tab wiring 40 and the solar cell 10 can be increased. In addition, as described above, since the stress received by the first portion 30a from the tab wiring 40 is relatively small, the first portion 30a can maintain flexibility enough to withstand the stress received from the tab wiring 40.

  Furthermore, the hardness of the second portion 30b is smaller than that of the first portion 30a. Therefore, sufficient flexibility to withstand the stress received from the sealing material 50 can be secured in the second portion 30b.

  Moreover, according to the manufacturing method of the solar cell module according to the present embodiment, when the tab wiring 40 is joined to the first portion 30a while heating, the hardness of the first portion 30a is larger than the hardness of the tab wiring 40. .

  Therefore, the first portion 30a can be embedded in the tab wiring 40 without being crushed. As a result, the amount of the first portion 30a embedded in the tab wiring 40 can be increased, and the tab wiring 40 can be prevented from peeling from the solar cell 10.

  Further, since the first portion 30a is mechanically press-fitted and embedded in the tab wiring 40 of the tab wiring 40, a sufficient electrical connection can be obtained.

  Further, in the solar cell module according to the present embodiment, the tab wiring 40 and the solar cell 10 are bonded by the resin adhesive 80. Therefore, the tab wiring 40 can be joined at a lower temperature than the alloy joining by forming the solder alloy layer. As a result, when the tab wiring 40 is thermally bonded, it is possible to suppress warping of the solar cell 10 that occurs due to a difference in linear expansion coefficient between the tab wiring 40 and the photoelectric conversion unit 20.

2. Second Embodiment Next, a solar cell module according to a second embodiment of the present invention will be described. In the said 1st Embodiment, although the silver paste which has the same composition was used for the 1st part 30a and the 2nd part 30b of the light-receiving surface side fine wire electrode 30, the silver paste which has a different composition is used in this embodiment. .

  Since the other configuration and manufacturing method are the same as those of the first embodiment, only differences from the first embodiment will be described.

(Method for manufacturing solar cell module)
First, as illustrated in FIG. 7A, first portions 30 a and 31 a to be joined to the tab wiring 40 are formed on the first region α on the light receiving surface side and the back surface side of the photoelectric conversion unit 20. Specifically, a silver paste is screen-printed on the first region α on the light receiving surface side, and after the silver paste is temporarily cured by heating at a temperature of several hundred degrees for several minutes, the first region on the back surface side A silver paste is screen-printed on α, and the silver paste is temporarily cured by heating at a temperature of a few hundred degrees for several minutes.

  Here, as the silver paste used for forming the first portions 30a and 31a, a silver paste having an epoxy thermosetting resin as a main skeleton and a soft molecular skeleton and silver particles dispersed therein is used. Thus, the hardness of the silver paste to which the soft molecular skeleton is added is larger than the hardness of the silver paste to which no soft molecular skeleton is added. The soft molecular skeleton mixed in the main skeleton has the same effect as increasing the resistance to expansion and contraction, that is, hardness, by adding aggregate and iron to cement.

  Next, as illustrated in FIG. 7B, the second portion 30 b that is not joined to the tab wiring 40 is connected to the first portion 30 a on the second region β on the light receiving surface side and the back surface side of the photoelectric conversion unit 20. To form. Specifically, a silver paste is screen-printed on the second region α on the light receiving surface side, and after the silver paste is temporarily cured by heating at a temperature of several hundred degrees for several minutes, the first region on the back surface side A silver paste is screen-printed on α, and the silver paste is temporarily cured by heating at a temperature of a few hundred degrees for several minutes. Thereafter, the first portions 30a and 31a and the second portions 30b and 31b are cured by heating the silver paste on both sides for about 30 minutes at a temperature of a few hundred degrees.

  Here, the silver paste used to form the second portion 30b is a silver paste in which silver particles are dispersed in an epoxy-based thermosetting resin solution similar to the silver paste used in the first embodiment. Use paste. Therefore, the hardness of the silver paste used for the first portion 30a is greater than the hardness of the silver paste used for the second portion 30b.

  Thereafter, the tab wiring 40 is thermally bonded to the solar cell 10 through the resin adhesive 80. During this heating, the hardness of the first portions 30 a and 31 b is greater than the hardness of at least the conductor 41 b portion of the tab wiring 40. Accordingly, the first portions 30a and 31b are embedded in the conductor 41b. Thereby, the first portions 30a and 31b and the tab wiring 40 are mechanically and electrically connected.

(Function and effect)
According to the solar cell module according to the present embodiment, the light-receiving surface side fine wire electrode 30 includes the first portion 30a to which the tab wiring 40 is joined and the second portion 30b to which the tab wiring 40 is not joined. The hardness of the material used for the portion 30a is larger than the hardness of the material used for the second portion 30b. The tab wiring 40 includes a low resistance body 41a and a conductor 41b, and the hardness of the first portion 30a is larger than the hardness of the conductor 41b when the tab wiring 40 is thermally bonded to the first portion 30a.

  Accordingly, the first portion 30a is embedded in the conductor 41b without being deformed (smashed). As a result, the amount of the first portion 30a embedded in the tab wiring 40 can be increased, and the tab wiring 40 can be prevented from peeling from the solar cell 10.

(Other embodiments)
Although the present invention has been described according 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, in the above embodiment, a solar cell substrate having a HIT structure has been described as an example. However, the present invention may be applied to a normal crystalline solar cell substrate having no HIT structure.

  In the above embodiment, the light receiving surface side thin wire electrode 30 has been mainly described. However, the back surface side thin wire electrode 31 has the same effect. Therefore, the effect of the present invention can be obtained if any one of the light receiving surface side thin wire electrode 30 and the back surface side thin wire electrode 31 includes a high hardness first portion and a low hardness second portion. it can.

  Moreover, in the said embodiment, although the material of the tab wiring 40 was demonstrated as copper foil, as long as electrical resistance is small as a material of a tab, what mixed iron, nickel, silver, or these was sufficient. Even so, the same effect can be obtained.

  Moreover, in the said embodiment, although the thing of the form shape | molded previously by the strip | belt-shaped film sheet was used as the resin adhesive 80, even if the resin adhesive is a paste-like thing, the same effect is acquired.

  Moreover, in the said embodiment, although the resin adhesive 80 was arrange | positioned in the substantially whole surface of 1st area | region (alpha), you may arrange | position the resin adhesive 80 partially.

  As described above, the present invention naturally includes various embodiments not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

  Hereinafter, the solar cell module according to the present invention will be specifically described with reference to examples. The present invention is not limited to those shown in the following examples, and can be implemented with appropriate modifications within the scope not changing the gist thereof.

Example 1
The solar cell module according to Example 1 was produced as follows.

  First, a 125 mm square solar cell substrate having a HIT structure was prepared.

  Next, using a screen printing method, a silver paste is applied in a predetermined pattern to the first region on the light receiving surface side of the solar cell substrate (region where the tab wiring is arranged), and heated at 150 ° C. for 5 minutes. Temporarily cured.

  Next, a silver paste was applied in a predetermined pattern to the first region (region where the tab wiring is arranged) on the back surface side of the solar cell substrate, and was temporarily cured by heating at 150 ° C. for 5 minutes. In addition, as a silver paste, the thing which disperse | distributed 5 vol.% Of 1 micrometer (phi) silver powder in the epoxy-type resin was used.

  Thereafter, the silver paste on both sides was heated at 200 ° C. for 30 minutes to be crosslinked and cured.

  Next, using a screen printing method, a silver paste is applied in a predetermined pattern on the second region (region where the tab wiring is not disposed) on the light receiving surface side of the solar cell substrate, and heated at 150 ° C. for 5 minutes. Temporarily cured.

  Next, a silver paste was applied in a predetermined pattern to the second region on the back side of the solar cell substrate (the region where the tab wiring is not disposed), and was temporarily cured by heating at 150 ° C. for 5 minutes. In addition, as a silver paste, the thing similar to the silver paste used for the 1st area | region was used.

Thereafter, the silver paste on both sides was heated at 200 ° C. for 30 minutes to be crosslinked and cured. As a result, the silver paste applied to the first region was completely cured. The hardness of the silver paste applied to the first region was 312 kg / mm ² (Vickers hardness), and the hardness of the silver paste applied to the second region was 256 kg / mm ² (Vickers hardness).

  Next, an epoxy resin adhesive was applied to substantially the entire first region of the photoelectric conversion portion, and tab wiring was disposed. For the tab wiring, a copper wire (width 2 mm, thickness 150 μm) outer periphery coated with solder (thickness 30 μm) was used. The solar battery was thermocompression-bonded (200 ° C., 2 MPa) with the tab wire sandwiched between them.

  Thereafter, an EVA sheet, a plurality of solar cells connected by tab wiring, an EVA sheet, and a back film were sequentially formed on the glass substrate, and the plurality of solar cells were encapsulated in EVA resin by a vacuum thermocompression bonding method.

(Example 2)
A solar cell module according to Example 2 was produced as follows.

In Example 1, the silver paste was applied to the second region and then cured by heating at 200 ° C. for 30 minutes, but in this example, it was cured by heating at 200 ° C. for 1 hour and 30 minutes. The hardness of the silver paste applied to the first region was 334 kg / mm ² (Vickers hardness), and the hardness of the silver paste applied to the second region was 312 kg / mm ² (Vickers hardness). Other manufacturing methods are the same as those in the first embodiment.

(Example 3)
A solar cell module according to Example 3 was produced as follows.

  In Example 1 above, an epoxy resin adhesive was applied to substantially the entire first region of the photoelectric conversion unit, but in this example, the resin adhesive was applied only to the periphery of the silver paste formed in the first region. Applied. Other manufacturing methods are the same as those in the first embodiment.

(Comparative Example 1)
A solar cell module according to a comparative example was produced as follows.

  In Example 1 above, the silver paste was applied to the first and second regions separately on the photoelectric conversion unit. However, in this comparative example, the silver paste was applied on the photoelectric conversion unit by one screen printing. did. Then, the silver paste was cured by heating at 200 ° C. for 30 minutes. Other manufacturing methods are the same as those in the first embodiment.

(Temperature cycle test)
A temperature cycle test was performed on the solar cell modules according to Examples 1 to 3 and the comparative example described above, and the outputs of the solar cell modules before and after the test were compared.

    The temperature cycle test used the method based on the temperature cycle test of JIS C8917. Specifically, a solar cell module is placed in a thermostatic bath, raised from 25 ° C. to 90 ° C. over 45 minutes, held at this temperature for 90 minutes, and then lowered to −40 ° C. over 90 minutes. Hold at temperature for 90 minutes, then increase to 25 ° C over 45 minutes. This was repeated for 400 cycles with 1 cycle (6 hours).

Thereafter, light of AM 1.5 and 100 mW / cm ² was irradiated from the light incident surface side of the solar cell module, and the output characteristics of the solar cell module were examined. The results are shown in Table 1. In the table, the output characteristic is expressed as a relative value when Example 1 is set to 100.

  From the table, the output characteristics of Examples 1 to 3 are larger than the output characteristics of the comparative example. This is a result of increasing the amount of embedding in the tab wiring because the hardness of the silver paste formed in the first region was increased according to the solar cell modules of Examples 1 to 3. That is, according to the solar cell modules of Examples 1 to 3, it was confirmed that the bonding between the tab wiring and the thin wire electrode can be strengthened.

  The reason why the output characteristic of Example 2 was smaller than the output characteristic of Example 1 was that the hardness of the silver paste formed in the second region was increased, so that damage received from the stress generated at the interface with the sealing material was accumulated. It depends on what was done.

  The reason why the output characteristics of Example 3 were smaller than the output characteristics of Example 1 was that the adhesive force to the photoelectric conversion part of the tab wiring was lowered because the resin adhesive was partially applied.

    As described above, according to the present invention, even when the tab wiring is directly bonded to the thin wire electrode, the reliability of the solar cell module is improved by firmly bonding the tab wiring and the thin wire electrode. It turned out that it can provide.

It is sectional drawing which shows the structure of the solar cell module 1 which concerns on 1st Embodiment. It is a top view of the solar cell 10 which concerns on 1st Embodiment. FIG. 3 is an enlarged view of a portion A in FIG. 2. It is sectional drawing in the BB cut surface of FIG. It is sectional drawing in the CC cut surface of FIG. It is sectional drawing which shows the structure of the photoelectric conversion part 20 which concerns on 1st Embodiment. It is a figure for demonstrating the manufacturing method of the solar cell module which concerns on 1st Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Solar cell module 10 ... Solar cell 20 ... Photoelectric conversion part 20a ... ITO film 20b ... p-type amorphous silicon layer 20c ... i-type amorphous silicon layer 20d ... n-type single crystal silicon substrate 20e ... i-type amorphous High-quality silicon layer 20f ... n-type amorphous silicon layer 20g ... ITO film 30 ... light-receiving side thin wire electrode 31 ... back side fine wire electrode 30a, 31a ... first portion 30b, 31b ... second portion 40 ... tab wiring 41a ... low Resistor 41b ... Conductor 50 ... Sealing material 60 ... Front side protective material 70 ... Back side protective material 80 ... Resin adhesive α ... First region β ... Second region

Claims (5)

A solar cell module comprising a front surface side protective material, a back surface side protective material, and a plurality of solar cells connected to each other by a wiring material between the front surface side protective material and the back surface side protective material,
The solar cell has a substrate and a plurality of thin wire electrodes formed on the surface of the substrate,
The fine wire electrode has a first part joined to the wiring material and a second part not joined to the wiring material,
The hardness of the first part is greater than the hardness of the second part,
The solar cell module, wherein the first portion is embedded in the wiring member. The wiring material has a low resistance layer and a conductor layer formed on an outer periphery of the low resistance layer,
The solar cell module according to claim 1, wherein the first portion is embedded in the conductor layer. The conductor layer is formed of solder,
The wiring member is bonded to the substrate via a resin adhesive,
The solar cell module according to claim 2, wherein a curing temperature of the resin adhesive is lower than a melting temperature of the solder. A method of manufacturing a solar cell module, comprising: a plurality of solar cells each having a substrate; and a plurality of thin wire electrodes formed on the surface of the substrate; and a wiring member that connects the plurality of solar cells to each other. ,
Forming a first portion of the thin wire electrode to be bonded to the wiring member on the surface of the substrate;
Step B for curing the first portion by heating the first portion;
Forming a second portion of the thin wire electrode that is not bonded to the wiring member on the surface of the substrate; and
A step D of curing the first part and the second part by heating the first part and the second part;
A step E of joining the wiring member to the first portion while heating the wiring member;
In the step E, the method of manufacturing a solar cell module, wherein the hardness of the first portion is larger than the hardness of the wiring member. A method of manufacturing a solar cell module, comprising: a plurality of solar cells each having a substrate; and a plurality of thin wire electrodes formed on the surface of the substrate; and a wiring member that connects the plurality of solar cells to each other. ,
Forming a first portion of the thin wire electrode to be bonded to the wiring member on the surface of the substrate;
Forming a second portion of the fine wire electrode that is not bonded to the wiring member on the surface of the substrate; and
A step C of curing the first part and the second part by heating the first part and the second part;
A step D for joining the wiring member to the first portion while heating the wiring member;
The hardness of the material used for the first part is greater than the hardness of the material used for the second part,
In the step D, the hardness of the first portion is larger than the hardness of the wiring member.

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