Patent Application
20140190548
1. Technical Field
The present technical field relates to a solar cell, a solar module, and a manufacturing method therefor.
2. Background Art
Solar modules including a plurality of solar cells connected to each other electrically using wiring members have attracted attention in recent years as an energy source with a low environmental impact. For example, a solar module is described in Patent Document 1 in which the solar cells and wiring members are bonded to each other using a resin adhesive.
Patent Document 1: Japanese Patent unexamined Publication No. 2010-238938
There has been growing demand in recent years for solar modules that are more reliable.
A solar cell in one aspect of the present disclosure includes a photoelectric conversion unit, an electrode, and a resin member. The electrodes are arranged on one main surface of the photoelectric conversion unit. Wiring members are connected electrically to the electrode. The resin members are arranged in the area including the electrode and positioned below the wiring members.
The solar cell in another aspect of the present disclosure includes a photoelectric conversion unit and an electrode. The electrode is arranged on one main surface of the photoelectric conversion unit. The electrode includes a plurality of finger portions and busbar portions. The solar cell in another aspect of the present disclosure also includes resin members arranged inside the area of the busbar portion on the one main surface.
The solar module in one aspect of the present disclosure includes solar cells and wiring members. The wiring members are connected electrically to the solar cells. Each solar cell includes a photoelectric conversion unit, an electrode, and resin members. The electrodes are arranged on one main surface of the photoelectric conversion unit. The electrodes are connected electrically to the wiring members. The resin members are each arranged on one main surface in an area including the electrode and positioned below the wiring members. The solar module also includes a resin adhesive layer. The resin adhesive layer bonds the wiring members to the surface of the solar cell including the surface of the resin member.
The present disclosure is also a method for manufacturing a solar module including the steps of: preparing a solar cell having a photoelectric conversion unit, an electrodes arranged on the one main surface of the photoelectric conversion unit, and resin members which are arranged inside areas including the electrode on the one main surfaces of the photoelectric conversion unit; and bonding the wiring members to the surfaces of the solar cell including the surface of the resin member using a resin adhesive to electrically connect the electrodes and the wiring members.
The present disclosure is able to provide a more reliable solar module.
The following is an explanation of examples of preferred embodiments. The following embodiments are merely examples. The present invention is not limited by the following embodiments in any way.
Further, in each of the drawings referenced in the embodiments, members having substantially the same function are denoted by the same symbols. The drawings referenced in the embodiments are also depicted schematically. The dimensional ratios of the objects depicted in the drawings may differ from those of the actual objects. The dimensional ratios of objects may also vary between drawings. The specific dimensional ratios of the objects should be determined with reference to the following explanation.
As shown in
The solar cells 10 are provided inside a bonding layer 13 filling the space between a first protecting member 14 and a second protecting member 15. The second protecting member 15 is provided on the side of the solar cells 10 which is exposed to light. The second protecting member 15 can be composed of a transparent member such as a transparent glass plate or plastic sheet. The first protecting member 14 is provided on the back surface side of the solar cells 10. The first protecting member 14 can be composed of resin film or resin film containing interposed metal foil. The bonding layer 13 can be composed of a resin such as an ethylene/vinyl acetate (EVA) copolymer or polyvinyl butyral (PVB).
If necessary, a frame may be mounted on the peripheral portion of the solar module 1. A terminal box may also be provided on the surface of the first protecting member 14 to draw output to the outside.
As shown in
The photoelectric conversion unit 20 has a first main surface 20a positioned on the second protecting member 15 side and a second main surface 20b positioned on the first protecting member 14 side. The first main surface 20a composes the light-receiving surface of the solar cells 10. The second main surface 20b composes the back surface of the solar cells 10.
The first electrode 31 is arranged on the first main surface 20a. The second electrode 32 is arranged on the second main surface 20b. Either the first electrode 31 or the second electrode 32 is the electrode that collects the minority carrier, and the other one is the electrode that collects the majority carrier. At least a portion of the first electrode 31 is arranged so as to overlap with the wiring member 11 in the thickness direction z. Similarly, at least a portion of the second electrode 32 is arranged so as to overlap with the wiring member 11 in the thickness direction z. Both the first electrode 31 and the second electrode 32 are connected electrically to the wiring member 11.
As shown in
As shown in
In the explanation of the example of the present embodiment, the busbar portions 31b, 32b are wider than the wiring member 11. However, the busbar portions may be thinner than the wiring member, or substantially the same width as the wiring member.
The first electrode 31 arranged on the first main surface 20a, or the light-receiving surface, preferably has a smaller surface area than the second electrode 32 in order to reduce light reception loss.
In the explanation of the example of the present embodiment, both the first electrode 31 and the second electrode 32 have a plurality of finger portions 31a, 32a and busbar portions 31b, 32b. However, there are no particular restrictions on the shape of the first electrode 31 and the second electrode 32. Either the first electrode 31 or the second electrode 32 may be a so-called busbar-less electrode having only finger portions. The second electrode 32 may be a thin-film electrode arranged substantially over the entire surface of the second main surface 20b.
A resin member 41 is arranged on the first main surface 20a of the photoelectric conversion unit 20 in the area including the first electrode 31 and beneath the wiring member 11. A resin member 42 is also arranged on the second main surface 20b of the photoelectric conversion unit in the area including the second electrode 32 and beneath the wiring member 11.
The resin member 41 has substantially the same thickness as the busbar portions 31b. The resin member 42 has substantially the same thickness as the busbar portions 32b. The wiring member 11 is bonded to the main surfaces of the solar cell 10 including the resin members 41, 42 using a resin adhesive layer 12. More specifically, in the present embodiment, the wiring member 11 is bonded by the resin adhesive layer 12 to at least some of the surface of the busbar portions 31b and to at least some of the surface of resin member 41. The wiring member 11 is bonded by the resin adhesive layer 12 to at least some of the surface of the busbar portions 32b and to at least some of the surface of resin member 42.
The resin adhesive layer 12 may contain a cured resin adhesive. The resin adhesive layer 12 may also contain a plurality of conductive members and a cured resin adhesive. When the resin adhesive layer 12 does not contain conductive members, there needs to attached directly between at least some of the wiring member 11 and the electrodes 31, 32. When the resin adhesive layer 12 contains conductive members, an electrical connection may be established via direct contact between the wiring member 11 and the electrodes 31, 32, or an electrical connection may be established via the conductive members.
There are no particular restrictions on the configuration of the wiring member 11. The wiring member 11 can be composed of a suitable conductive material, including metals such as Cu or Ag, or alloys containing these metals. The wiring member 11 may have a coating layer containing a conductive material such as solder. The wiring member 11 may also have an uneven surface.
As shown in
As shown in
The wiring member 11 is bonded via the resin adhesive layer 12 to the surfaces of the solar cells 10 including the surfaces of the resin members 41, 42. The bonding strength of the wiring member 11 to the solar cells 10 is increased by bonding the resin members 41, 42 to the resin adhesive layer 12. The result is a solar module 1 with improved reliability.
In the solar module 1, the wiring member 11 and resin member 41 are bonded in several spots in the x-direction, and the wiring member 11 and resin member 42 are bonded in several spots in the x-direction. Because there are several areas in the extension direction of the wiring member 11 in which the bonding strength of the wiring member 11 and the solar cells 10 has been improved, a solar module 1 can be obtained with even better reliability.
In the solar module 1, the resin member 41 is surrounded by busbar portions 31b. In this way, the bonding strength of the electrical connection between the wiring member 11 and the busbar portions 31b is improved near the areas where the wiring member 11 and the resin member 41 have been bonded with greater bonding strength. This suppresses any decrease in electrical connection properties between the wiring member 11 and busbar portions 31b. This also suppresses any decrease in electrical connection properties between the wiring member 11 and busbar portions 32b. The result is a solar module 1 with even better reliability.
In the solar module 1, the busbar portions 31b are arranged below the wiring member 11 whose bonding strength to the solar cell 10 has been improved by the resin member 41. The resin member 41 acts to prevent the busbar portions 31b from peeling away from the first main surface 20a of the photoelectric conversion unit 20. This suppresses any deterioration in the electrical connection properties between the busbar portions 31b and the first main surface 20a of the photoelectric conversion unit 20 even when force is applied in a direction that would cause the wiring member 11 to peel off. This also suppresses any deterioration in electrical connection properties between the busbar portions 32b and the second main surface 20b of the photoelectric conversion unit. The result is a solar module 1 with even better reliability. Because the reliability of solar modules including solar cells having busbar portions 31b, 32b formed using a plating method can be improved, the industrial effects are especially advantageous.
From the standpoint of improving the bonding strength between the wiring member 11 and the solar cells 10, the resin members 41, 42 are preferably composed of at least one type of resin selected from a group including polyester resins, ethylene/vinyl acetate copolymers, acrylic resins, epoxy resins and urethane resins, and the resin adhesive layer 12 preferably includes at least one type of cured resin adhesive selected from a group including EVA resins, acrylic resins, epoxy resins and urethane resins. The resin members 41, 42 are more preferably composed of at least one type of resin selected from a group including acrylic resins and epoxy resins, and the resin adhesive layer 12 more preferably includes at least one type of cured resin adhesive selected from a group including acrylic resins and epoxy resins.
The following is an explanation of an example of a method for manufacturing a solar module 1.
First, a photoelectric conversion unit 20 is prepared. The photoelectric conversion unit 20 can be prepared using any method well known in the art.
Next, as shown in
Next, the first electrode 31 and the second electrode 32 are formed to complete the solar cell 10. The first electrode 31 and the second electrode 32 can be formed using a method such as screen printing.
When resin member 41 is formed, a resin layer may be formed substantially over the entire first main surface 20a, and then the resin layer may be removed only in the areas where the electrode 31 is to be formed. In this case, the remaining resin layer serves as a mask, making the formation of the first electrode 31 easier using the plating method. Resin member 42 can be formed in the same way.
Next, a plurality of solar cells 10 created in this way are provided and connected electrically using a wiring member 11. More specifically, the wiring member 11 is bonded via a resin adhesive 12a to the surface of a solar cell 10 including the resin member 41, and the wiring member 11 is bonded via resin adhesive 12a to the back surface of the solar cell 10 including the surface of resin member 42. This step is repeated to electrically connect a plurality of solar cells 10 using a wiring member 11.
Afterwards, the plurality of solar cells 10 connected electrically via a wiring member 11 are sealed using a bonding layer 13 between a first protecting member 14 and a second protecting member 15. More specifically, a resin sheet such as an EVA sheet is placed on top of the second protecting member 15. The solar cells 10 are placed on this resin sheet. A resin sheet such as an EVA sheet is placed on this, and a first protecting member 14 is placed on top of this. Heat can be applied in a reduced pressure environment to bond and laminate these layers and complete the solar module 1.
When the solar cells 10 are prepared, there are no particular restrictions on the relationship between the thickness of resin member 41 and the electrode 31. However, as shown in
In this way, the stress applied between the wiring member 11 and the solar cells 10 can be relaxed by the deformation of the resin members 41, 42. In other words, the application of a large amount of stress on the solar cells can be suppressed. As a result, damage to the solar cells 10 can be suppressed, and the yield of solar modules 1 can be increased.
Heat is preferably applied while the wiring member 11 and the solar cells 10 are being bonded. This makes the resin members 41, 42 more likely to become deformed during the connection step. Therefore, the application of a large amount of stress to the solar cells 10 can be effectively suppressed, and damage to the solar cells 10 can be more effectively suppressed.
From this standpoint, resin member 41 and resin member 42 are preferably arranged so as to partially overlap in plan view. Because this suppresses even more the application of a large amount of stress to the solar cells during the connection step, the yield of solar modules 1 can be increased.
The wiring member 11 is preferably bonded to one main surface of a solar cell 10 at the same time the wiring member 11 is bonded to the other main surface, but this can also be performed separately. This can further reduce the amount of stress applied to the solar cells 10, and can also suppress warping of the solar cells 10 due to the difference in the thermal expansion coefficients of the wiring member 11 and the solar cell 10.
The following is an explanation of additional examples of preferred embodiments. In the following explanation, components with substantially the same functions as those in the first embodiment are denoted by the same reference numbers, and further explanation of these components has been omitted.
In the explanation of the example of the first embodiment, a resin member 41, 42 was provided on both sides of the solar cell 10. In the solar module 2 of the second embodiment, as shown in
A resin member 41 may be provided only on the back surface side of the solar cell 10, but the resin member 41 is preferably provided on the light-receiving side when the first electrode 31 on the light-receiving surface side has a smaller surface area than the second electrode 32 on the back surface side. This is able to reduce the large amount of stress on the first electrode 31 caused by the application of pressure on the wiring member 11 during the connection step.
In the explanation of the example of the first embodiment, the resin members 41, 42 are not provided in the area including the ends of the busbar portions 31b, 32b in the x-direction, which is the direction in which the wiring member 11 extends. However, in the solar module of the third embodiment, as shown in
In the fourth embodiment, as shown in
In the explanation of the example in the first embodiment, the resin members 41 have substantially the same shape, and the resin members 42 have substantially the same shape. However, in the fifth embodiment, as shown in
In the explanation of the example of the first embodiment, each of the first and second electrodes 31, 32 has a plurality of finger portions 31a, 32a, and busbar portions 31b, 32b connected to these electrically. However, in the sixth embodiment, as shown in
There are no particular restrictions on the method used to form the planar shaped second electrode 32. The second electrode 32 can be formed using a screen printing method, a plating method, a vapor deposition method, or a sputtering method.
A terminal portion may also be provided on the planar shaped second electrode 32 and bonded to the wiring member 11.
The following is a more detailed explanation of the present disclosure with reference to specific test examples. However, the present invention is not restricted in any way to these test examples. Various changes and improvements are possible without departing from the spirit and scope of the present disclosure.
First, as shown in
Two of the samples S2 for the second test example shown in
An end of the wiring member 53 of each sample S1, S2 prepared in the first and second test examples was pulled at a 90-degree angle with respect to the plane direction of the photoelectric conversion unit 51 and a portion of the wiring member 53 was peeled. The strength at this time was measured at the six points (A-F) shown in
Average Peeling Strength in First Test Example: 0.4 N
Average Peeling Strength in Second Test Example: 1.2 N
It is clear from the results that the bonding strength of the wiring member can be improved by bonding a portion of the wiring member to a resin member.
The present disclosure includes many different embodiments not described herein. For example, a resin member may be provided which spans the entire busbar portion in the length direction.
Either one of the first and second electrodes may be a busbarless electrode composed of a plurality of finger portions without a busbar portion.
The busbar portion may be provided in a zigzag pattern.
The present disclosure includes many other embodiments not described herein. Therefore, the technical scope of the present disclosure is defined solely by the items of the disclosure specified in the claims pertinent to the above explanation.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2011/072350 | Sep 2011 | US |
| Child | 14205373 | US |
