JP6008475B2 - Manufacturing method of solar cell module - Google Patents

Description

The present invention, a solar cell module comprising a solder joint body and the object to be solder article and thick current collector sheet for a solar cell which is used as a wiring inside such as a solar cell module is bonded via a solder containing a specific component It relates to the manufacturing method .

  In recent years, solar cells as a clean energy source have attracted attention due to the growing awareness of environmental issues. In general, a solar cell module constituting a solar cell is referred to as a transparent front substrate, a front surface side sealing material sheet, a solar cell element, a back side sealing material sheet, and a back surface protection sheet (back surface protection sheet or the like) from the light receiving surface side. .) Are stacked in order, and have a function of generating power when sunlight enters the solar cell element.

  A plurality of solar cell elements that generate power inside the solar cell module are usually provided inside the solar cell module, and are configured to obtain necessary voltages and currents by connecting them in series and parallel. . In order to wire a plurality of solar cell elements inside a solar cell module, for example, a solar cell current collector sheet in which a metal that becomes a conductive pattern is laminated on the surface of a resin sheet as a base material is used (Patent Document). 1). And the metal foil which is the electrically conductive pattern provided in the current collection sheet for solar cells, and the output electrode of a solar cell element are electrically joined by soldering.

  In order to provide a conductive pattern on the surface of a resin sheet that is a base material for a solar cell current collector sheet, for example, similarly to a printed wiring board, first, a metal is laminated on the entire surface of the base material, and then this metal May be etched to a desired conductive pattern by photolithography.

JP 2007-081237 A

  By the way, in particular, in a circuit in which the wiring width, that is, the width between the conductive patterns constituting the circuit is narrow, the metal foil that is the conductive pattern provided on the solar cell current collector sheet and the output electrode of the solar cell element are provided. When joining by soldering, a plurality of adjacent conductive patterns may be short-circuited by solder. And the method of preventing such a short circuit effectively was calculated | required.

  The present invention has been made in view of the above situation. When a metal foil, which is a conductive pattern provided on a solar cell current collector sheet, and a soldered article such as an output electrode of a solar cell element are joined by soldering, adjacent to the solar cell current collector sheet by soldering It is an object of the present invention to provide a solar cell current collector sheet and a method for manufacturing the same, which can prevent a plurality of conductive patterns from being short-circuited.

  The present inventors, due to the cross-sectional shape in the cross-sectional view in the thickness direction of the conductive pattern, during the soldering process, the alloy component that is a component of the solder is quickly transferred to the plane portion on the conductive convex portion, It has been found that the resin component, which is another component of the solder, fills the conductive recess quickly.

  Conventionally, as for the shape of the conductive pattern in the cross-sectional view in the thickness direction, both side walls of the non-conductive recess sharing the wall surfaces of the plurality of conductive protrusions as the side walls with respect to the base of the solar cell current collector sheet It was considered desirable to be vertical. However, the inventors of the present invention have a reverse taper in which both side walls of the non-conductive recess in the solar cell current collector sheet are spread from the surface side of the resin base toward the plane of the conductive projection. It has been found that the above-mentioned effects can be obtained by forming the film in a shape.

  Furthermore, as a result of intensive studies, the present inventors have adjusted the cross-sectional shape of the conductive pattern to the shape as described above by adjusting the concentration of the immersion liquid and the etching time in the etching process of the metal foil that is the conductive pattern. When the metal foil, which is a conductive pattern provided on the solar cell current collector sheet, and a soldered article such as an output electrode of the solar cell element are joined by soldering, the solar cell current collector can be formed by soldering. It has been found that a plurality of adjacent conductive patterns on the sheet can be prevented from being short-circuited, and the present invention has been completed. Specifically, the present invention provides the following.

  (1) The present invention is a solar cell current collector sheet in which a strip-shaped conductive pattern made of a metal foil having a predetermined thickness is formed on the surface of a resin base material, wherein the conductive pattern includes a plurality of conductive protrusions. And a non-conductive recess that shares the surface side of the resin base between the conductive convex portions and a wall surface of the conductive convex portion as a side wall, and both side walls of the non-conductive concave portions are the resin base It is the current collection sheet for solar cells characterized by the reverse taper shape spreading from the surface side of a material.

  (2) Moreover, this invention is a collector sheet for solar cells as described in (1) whose angle which the bottom part of the said nonelectroconductive recessed part and both side walls make is in the range of 95 degree | times to 120 degree | times.

  (3) In the present invention, the wiring width on the surface of the conductive convex portion is 0.2 to 5.0 mm, and the width of the bottom portion of the nonconductive concave portion is 0.2 to 5.0 mm. Or it is a collector sheet for solar cells as described in (2).

  (4) Further, according to the present invention, the solar cell current collector sheet according to any one of (1) to (3) and a soldered article are joined via solder, and the solder is composed of a solder alloy and an epoxy resin. A solder joint including

  (5) Further, according to the present invention, the solder alloy forms a conductive portion together with the joint on the conductive convex portion, and the epoxy resin fills the non-conductive concave portion together with the joint to form an insulating portion (4 ) Solder joints as described above.

  (6) Further, the present invention provides the solder according to (4) or (5), wherein the predetermined thickness of the metal foil is 10 to 50 μm, and a step between the conductive convex portion and the nonconductive concave portion is 50 μm or less. It is a joined body.

  (7) Further, in the present invention, the solder joined body according to (4) to (6) constitutes a part of the solar cell module, the electrode of the solar cell element that is the soldered article, the conductive convex portion, Is a solar cell module joined by soldering.

  According to the present invention, in the formation of the conductive pattern, the both side walls of the non-conductive concave portion sharing the wall surfaces of the plurality of conductive convex portions as the side walls are directed from the surface side of the resin base to the flat portion side of the conductive convex portion. By making it the reverse taper shape which spreads, the collector sheet for solar cells which can prevent a short circuit effectively and its manufacturing method are provided.

It is a perspective view which shows typically a mode that the collector sheet for solar cells of this invention is joined to a solar cell element. It is a top view showing typically one embodiment of the current collection sheet for solar cells of the present invention. It is sectional drawing which follows the XX line of FIG. 2, and is sectional drawing which showed the general sectional shape of the conductive pattern by a prior art. It is the perspective view which showed typically one preferable shape of the electroconductive pattern on the collector sheet for solar cells in embodiment of this invention. It is sectional drawing which follows the XX line of FIG. 2, and is sectional drawing which showed the preferable shape of the electrically conductive recessed part on the collector sheet for solar cells in embodiment of this invention. It is sectional drawing which follows the XX line of FIG. 2, and is sectional drawing which showed other preferable one shape of the electroconductive pattern on the collector sheet for solar cells in embodiment of this invention. It is sectional drawing which showed the example of the unpreferable shape about the cross-sectional shape of the electrically conductive pattern on the collector sheet for solar cells. It is the schematic diagram which showed the solder joining process of the collector sheet for solar cells of this invention, and a solar cell element, (a) Before joining, (b) It is sectional drawing which shows the state after joining.

Hereinafter, an embodiment of a current collector sheet for solar cells and a method for producing the same of the present invention will be described.
<Current collector sheet for solar cell>
First, an embodiment of the current collector sheet 1 for solar cells of the present invention will be described with reference to FIG. FIG. 1 is a perspective view schematically showing a state in which a solar cell current collector sheet 1 of the present invention is joined to a solar cell element 5.

  In the solar cell current collector sheet 1 of the present embodiment, a conductive pattern 3 is formed on the surface of a resin substrate 2. The back surface side (non-light-receiving surface side) of the solar cell element 5 is joined so as to cover the conductive pattern 3. A plurality of solar cell elements 5 are provided on the solar cell current collector sheet 1 and are configured to obtain necessary voltages and currents when they are connected in series and parallel. In order to wire a plurality of solar cell elements 5 on the solar cell current collector sheet 1, the conductive pattern 3 that is a wiring provided on the solar cell current collector sheet 1 and the electrode 51 of the solar cell element 5 are Electrical bonding is performed by soldering as shown in 8 (a) and 8 (b).

  Here, the electrode 51 of the solar cell element 5 is an electrode for outputting the electric power generated by the solar cell element 5 by receiving light to the outside of the solar cell element 5. Although not particularly limited, this electrode is made of silver or a silver compound as an example.

  As the solder used in the soldering process, an alloy / resin composite solder composed of a conductive alloy component and a highly insulating resin component is used. As an example of the alloy component, tin, bismuth or the like having a melting point of around 150 ° C. is preferable. An epoxy resin is preferable as the resin component. Details of the soldering will be described later.

  The resin base material 2 is a resin molded into a sheet shape. Here, the sheet form is a concept including a film form, and there is no difference between them in the present invention. Examples of the resin constituting the resin substrate 2 include polyethylene resin, polypropylene resin, cyclic polyolefin resin, polystyrene resin, acrylonitrile-styrene copolymer, acrylonitrile-butadiene-styrene copolymer, polyvinyl chloride resin, Fluorine resin, poly (meth) acrylic resin, polycarbonate resin, polyester resins such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyamide resins such as various nylons, polyimide resins, polyamideimide resins Examples thereof include resins, polyaryl phthalate resins, silicone resins, polysulfone resins, polyphenylene sulfide resins, polyether sulfone resins, polyurethane resins, acetal resins, and cellulose resins. Among these, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyamide-imide resin, polyimide from the viewpoint that good heat resistance in the soldering process can be imparted to the solar cell collector sheet 1. Based resins are preferred, and polyethylene terephthalate (PET), polyethylene naphthalate (PEN), etc. are most preferred.

  What is necessary is just to set the thickness of the resin base material 2 suitably according to the intensity | strength, thinness, etc. which are requested | required of the collector sheet 1 for solar cells. Although the thickness of the resin base material 2 is not specifically limited, 20-250 micrometers is mentioned as an example.

  The conductive pattern 3 is an electrical wiring formed on the surface of the solar cell current collector sheet 1 so as to have a desired wiring shape. The conductive pattern 3 is a layer made of, for example, copper. In order to form the conductive pattern 3 on the surface of the resin base material 2, a method of bonding a copper foil to the surface of the resin base material 2 and then patterning the copper foil by an etching process or the like is exemplified. In order to join the copper foil to the surface of the resin base material 2, a known method can be used without particular limitation. Examples of such a method include a method of adhering copper foil to the surface of the resin base material 2 with an adhesive, a method of depositing copper on the surface of the resin base material 2, and the like from the viewpoint of cost. A method of adhering the foil to the surface of the resin substrate 2 with an adhesive is advantageous. Among these, a method of adhering the copper foil to the surface of the resin substrate 2 by a dry laminating method using an adhesive such as urethane, polycarbonate, or epoxy is preferable.

  What is necessary is just to set the thickness of the conductive pattern 3 suitably according to the magnitude | size of the electric current resistance requested | required of the collector sheet 1 for solar cells. Although the thickness of the conductive pattern 3 is not specifically limited, As an example, 10-50 micrometers is mentioned.

  In the conductive pattern 3, the level difference between the conductive convex portion and the nonconductive concave portion is equal to the thickness of the conductive pattern 3.

In the conductive pattern 3, the wiring width W ₁ (shown in FIG. 5) on the surface of the conductive convex portion is 0.2 to 5.0 mm, and the width W ₂ (shown in FIG. 5) of the bottom portion 3a of the non-conductive concave portion is 0.2 to 5.0 mm.

  FIG. 2 is a front view schematically showing a part of the solar cell current collector sheet 1, and FIG. 3 is taken along line XX of FIG. 2 in a conventional general solar cell current collector sheet. It is sectional drawing. As shown in FIG. 3, in the conventional general solar cell current collector sheet, both side walls of the non-conductive recesses constituting the non-conductive portion 40 in a cross-sectional view in the thickness direction of the conductive pattern 30 of the non-conductive portion 40 The corner portion 30c formed by the surface of the resin base material 2 is generally a right angle P, and it has been considered desirable to be formed in such a shape. However, the fact that the corner 30c is a right angle P is not an appropriate shape for solving the problem of the present invention.

  FIG. 4 is a perspective view showing the shape of the conductive pattern 3 on the solar cell current collector sheet 1 in the present embodiment, and FIG. 5 is a cross-sectional view taken along line XX of FIG. 2 in the present embodiment. . As shown in FIGS. 4 and 5, the surface of the non-conductive concave portion constituting the non-conductive portion 4 is composed of a bottom 3 a that is the surface of the resin base material 2, and both side wall portions 3 b that constitute a boundary surface with the conductive portion. In the cross-sectional view in the thickness direction of the corner 3c conductive pattern 3 where the bottom 3a and both side walls 3b intersect, the obtuse angle Q is more than 90 degrees. Further, both side wall portions 3b of the non-conductive concave portion have an inverse taper shape in which the width is narrowed toward the bottom portion 3a from the surface side of the resin base material 2. In the solar cell current collector sheet 1 of the present invention, by having such a configuration, during the soldering process, the alloy component that is a component of the solder is quickly transferred to the planar portion 3d of the conductive convex portion, On the other hand, the resin component which is another component of the solder quickly fills the non-conductive recess. Therefore, a short circuit can be prevented. The obtuse angle Q is preferably 95 to 120 degrees as measured with an optical microscope. In addition, as a result of making the corner 3c an obtuse angle Q, the both side walls 3b have a reverse taper shape in which the width becomes narrower as it is closer to the bottom 3a, and the rising taper angle R is (180-Q) degrees.

  FIG. 6 is a cross-sectional view taken along line XX of FIG. 2, and is another example of the present invention. In this example, in the cross-sectional view of the conductive pattern 31 in the thickness direction, the corner portion 31e where the planar portion 31d of the conductive pattern 31 and the side wall portions 31b intersect is formed by the curved portion S as shown in FIG. The taper angle R is the same as in FIG. The solar cell current collector sheet 1 can effectively prevent a short circuit also by having such a configuration. The curved portion S is measured with an optical microscope, and preferably the radius of curvature r from the center O is 1.0 to 5.0 μm, and the formed angle s is in the range of 40 degrees to 90 degrees. .

  FIG. 7A and FIG. 7B are examples of the cross-sectional shape in the cross-sectional view in the thickness direction of the conductive pattern in which the short circuit is likely to occur in the solar cell collector sheet 1. Since the angle of the cross-sectional shape 32e of the conductive pattern 32 shown in FIG. 7A is 90 degrees, the solder alloy component hardly shifts to the flat portion 32d of the conductive pattern 32 in the soldering process. Since the angle of the cross-sectional shape 33e of the conductive pattern 33 shown in FIG. 6B is an acute angle of less than 90 degrees, the solder alloy component further shifts to the plane portion 33d of the conductive pattern 33 in the soldering process. Hateful. Therefore, as a result, the shape is likely to cause a short circuit.

<Method for producing solar battery collector sheet>
Next, an embodiment of a method for producing the solar cell current collector sheet 1 of the present invention will be described. In the following description, the description overlapping with the content already described will be omitted, and different portions will be mainly described.

  The solar cell current collector sheet 1 described above is manufactured by the method for manufacturing the solar cell current collector sheet 1 of the present embodiment. In the manufacturing method of the solar cell current collector sheet 1 of this embodiment, a laminated sheet in which a conductive layer made of copper is laminated on the surface of the resin base 2 is used. The solar cell current collector sheet 1 is produced by subjecting this laminated sheet to an etching step and a peeling step. Hereinafter, the etching process and the peeling process will be described.

[Etching process]
First, the etching process will be described. In this step, an etching mask (not shown) patterned in the shape of a desired conductive pattern 3 is formed on the surface of the laminated sheet, and then an etching process is performed, so that the conductive layer in a portion not covered with the etching mask is obtained. This is a step of removing.

  As already explained, the laminated sheet used in this step is one in which a conductive layer made of copper is formed on the surface of the resin substrate 2. About the method of forming the conductive layer which consists of copper on the surface of the resin base material 2, the method of adhere | attaching copper foil on the surface of the resin base material 2 with an adhesive agent, the method of vapor-depositing copper on the surface of the resin base material 2, etc. Although illustrated, from the viewpoint of cost, a method of adhering the copper foil to the surface of the resin substrate 2 with an adhesive is advantageous. Among these, a method of adhering the copper foil to the surface of the resin substrate 2 by a dry laminating method using an adhesive such as urethane, polycarbonate, or epoxy is preferable.

  In this step, first, the etching mask (not shown) patterned in the shape of the desired conductive pattern 3 is formed on the surface of the laminated sheet (that is, the surface of the conductive layer). The etching mask is provided so that the conductive layer that will become the conductive pattern 3 in the future will be free from corrosion by the immersion liquid in an etching process described later. The method for forming such an etching mask is not particularly limited. For example, the etching mask may be formed on the surface of the laminated sheet by developing a photoresist or a dry film after exposure through the photomask, The etching mask may be formed on the surface of the laminated sheet by a printing technique such as an inkjet printer. The etching mask needs to be able to be stripped with an alkaline stripping solution in a stripping step described later. From such a viewpoint, it is preferable to produce the etching mask using a photoresist or a dry film.

  At this time, normally, the width of the etching mask is made wider by α on both sides than the width T of the conductive pattern 3 to be produced (that is, T + 2α in the whole width), so that the rising angle close to vertical (R in FIG. 5). In the present invention, the taper angle R as shown in FIGS. 5 and 6 can be obtained by reducing α.

  Next, the etching process in an etching process is demonstrated. This process is a process of removing the conductive layer in a portion not covered with the etching mask with the immersion liquid. By passing through this treatment, portions other than the portion to be the conductive pattern 3 in the conductive layer are removed. Therefore, the conductive layer is formed in the shape of the desired conductive pattern 3 on the surface side of the resin substrate 2. Will remain. As a result, an adhesive layer (not shown) remains on the surface side of the resin base material 2 constituting the bottom 3a of the non-conductive recess.

Specifically, for the immersion liquid in the etching step, for example, ferric chloride (FeCl ₃ ) having a Baume specific gravity of 30 to 45 can be used.

  At this time, in the present invention, by changing the etching solution specific gravity and the etching processing time, it is possible to obtain a cross-sectional shape that does not generate a singular point as described above. Specifically, the Baume specific gravity is decreased from the normal conditions to increase the etching processing capacity, and the etching processing time is reduced by a corresponding amount. By doing so, the cross-sectional shape in the present invention can be obtained by changing the shape of the corner without changing the etching amount. The preferred Baume specific gravity for obtaining the shape of the corner in the present invention is 30 to 45.

[Peeling process]
Next, the peeling process will be described. This step is a step of removing the etching mask using an alkaline stripping solution. Through this step, the etching mask is removed from the surface of the conductive pattern 3. Examples of the alkaline stripping solution used in the stripping step include an aqueous solution of caustic soda.

<Solar cell module and manufacturing method of solar cell module>
A solar cell module using the solar cell current collector sheet 1 as described above is also one aspect of the present invention. Next, an embodiment of these inventions will be described.

  In one embodiment of the solar cell module of the present invention, the surface of the conductive pattern 3 in the solar cell current collector sheet 1 and the electrode 51 of the solar cell element are joined by soldering. Specifically, the conductive pattern 3 is joined to the electrode 51 of the solar cell element by soldering. Thereby, the solar cell current collector sheet 1 and the solar cell element 5 are electrically joined to form an electrical wiring inside the solar cell module.

[Soldering]
Here, soldering will be described with reference to FIGS. 8 (a) and 8 (b). As shown in FIG. 8 (a), in the soldering process, the solder 6 containing the alloy component and the resin component having insulating properties is applied to the substantially entire surface of the solar cell element 5 on the electrode 51 side, and then the solar cell current collector is applied. It overlaps with the sheet 1 and then reflows to heat-bond the solar cell current collector sheet 1 and the solar cell element 5. At this time, as shown in FIG. 8B, the alloy component 61 is moved onto the flat surface portion 3d of the conductive pattern 3 while leaving the solder resin component 62 in the non-conductive portion 4, so that the alloy component 61 and the resin component are transferred. 62 is phase-separated and the electrode 51 of the solar cell element and the conductive pattern 3 are joined with the alloy component 61 of the solder. In this case, it is necessary to quickly separate the alloy component 61 and the resin component 62 by reflow, but the solar cell current collector sheet 1 of the present invention has both side walls of the non-conductive recesses constituting the non-conductive portion 4, Due to the reverse taper shape with the width narrowing toward the surface side of the resin base material 2, the transition of the alloy component 61 onto the flat portion 3 d of the conductive pattern 3 occurs promptly. On the other hand, the resin component 62 is stored in the non-conductive recess so as to fill the non-conductive recess constituting the non-conductive portion 4. Regarding the fixing of the resin component 62 to the non-conductive portion 4 as well, both side walls of the non-conductive recess constituting the non-conductive portion have an inverse taper shape whose width narrows toward the bottom of the non-conductive recess, Promptly promoted.

  The resin component 62 filling the non-conductive recesses constituting the non-conductive portion 4 fills the gap formed between the solar cell element and the resin base material 2 to join the solar cell current collector sheet 1 and the solar cell element 5. As well as effectively preventing a short circuit as an insulator.

  The joined body of the solar cell current collector sheet 1 and the solar cell element 5 includes a transparent front substrate (not shown), a front-side sealing material sheet (not shown), and a back-side sealing material sheet as necessary. (Not shown), a back surface protection sheet (not shown), etc. are combined to form a solar cell module.

  As an example of such a solar cell module, from the surface side of the solar cell module, a transparent front substrate (not shown), a surface side sealing material sheet (not shown), the solar cell element 5, and a solar cell current collector sheet 1, a back surface side sealing material sheet (not shown) and a back surface protection sheet (not shown) are stacked in this order and integrated by vacuum heat laminating. It is not limited to a structure, What is necessary is just to comprise suitably considering the performance requested | required of a solar cell module.

  As described above, the solar cell current collector sheet, the solar cell current collector sheet manufacturing method, the solar cell module, and the solar cell module manufacturing method have been specifically described with reference to the embodiment and the embodiment thereof. The present invention is not limited to the above embodiments and embodiments, and can be implemented with appropriate modifications within the scope of the configuration of the present invention.

  For example, in the said embodiment and embodiment, although the solar cell current collection sheet | seat 1 was the solar cell current collection sheet | seat for internal wiring in a solar cell module, uses other than a solar cell module may be sufficient. Since the solar cell current collector sheet of the present invention can prevent a short circuit in a high-density wiring having a pitch between wirings of 0.5 mm or less, it is also suitably used in a high-density wiring incorporated in addition to a solar cell module.

  Hereinafter, the present invention will be described in more detail with reference to comparative examples and examples. In addition, this invention is not limited to a following example.

<Comparative example>
First, a comparative example will be described. A laminated sheet in which polyethylene terephthalate (PET, thickness: 100 μm) molded into a sheet was used as the resin substrate 2 and a 35 μm copper foil was laminated on the surface with an adhesive was used. An etching mask of L (line) 500 μm / S (space) 500 μm was produced on the surface of the laminated sheet.

  Thereafter, using the ferric chloride aqueous solution having a Baume specific gravity of 40 as an immersion liquid, the laminated sheet on which the etching mask was formed was immersed in the immersion liquid for 1.5 minutes, and then washed with pure water. Thereby, the copper foil of the location which is not coat | covered with the etching mask was removed.

  Next, as a peeling step, the laminated sheet subjected to the etching treatment was immersed in a peeling solution for 1.5 minutes. Then, it was washed with pure water. Thereby, the conductive pattern 32 which consists of a conductive layer which consists of copper foil was formed in the surface of a base material.

  At this time, the cross-sectional shape in the thickness direction of the conductive pattern 32 was a rectangular shape substantially the same as the shape shown in FIG. In this state, when the solder joined body of the solar cell current collector sheet and the solar cell element as shown in FIG. 8 is formed, the solder alloy component 61 is transferred onto the planar portion 32d of the solder alloy component 61 in the soldering process. Insufficient, resulting in a short circuit.

<Example>
Next, examples will be described. The ferric chloride aqueous solution used as the immersion liquid in the etching step was the same as the comparative example except that the Baume specific gravity was 30 and the immersion time was 1.3 minutes. Thereby, the conductive pattern 3 which consists of a conductive layer which consists of copper foil was formed in the surface of a base material. At this time, the cross-sectional shape in the thickness direction of the conductive pattern 3 was substantially the same taper shape as that shown in FIG. 5 (Q = 100 degrees, R = 80 degrees). That is, in the soldering process, the solder alloy component 61 is likely to be transferred onto the planar portion 3d of the conductive pattern 3, and as a result, a shape in which a short circuit is unlikely to occur is obtained. The cross-sectional shape was obtained by decreasing the Baume specific gravity of the immersion liquid to increase the dissolution rate of copper, and by increasing the etching processing speed accordingly. In this state, when the solder joined body of the solar cell current collector sheet and the solar cell element as shown in FIG. 8 is formed, the solder alloy component 61 is transferred to the planar portion 3d of the conductive pattern 3 in the soldering process. Occurred and no short circuit occurred.

  As described above, the cross-sectional shape in the thickness direction of the conductive pattern 3 can be controlled by setting the condition of the Baume specific gravity of the immersion liquid in the etching step to an appropriate value. And the collector sheet for solar cells which can prevent that a some electroconductive pattern short-circuits by performing such control can be manufactured.

  The method for controlling the cross-sectional shape in the thickness direction of the conductive pattern 3 is not limited to the above method. The control can also be performed by appropriately changing other conditions in the etching step. For example, the cross-sectional shape can be controlled also by adjusting the width of a portion not covered with the etching mask when forming the etching mask. It is possible to manufacture the solar cell current collector sheet 1 according to the present invention also by another method capable of controlling the cross-sectional shape of the conductive pattern 3 in the thickness direction.

DESCRIPTION OF SYMBOLS 1 Current collecting sheet for solar cells 2 Resin base material 3 Conductive pattern 4 Nonconductive part 5 Solar cell element 6 Solder Q The obtuse angle made by the bottom part of a nonconductive recessed part and both side walls

Claims (1)

A solder joined body in which a solar cell current collector sheet on which a belt-like conductive pattern made of a metal foil of a predetermined thickness is formed on the surface of a resin base material and a soldered article are joined via solder A method for manufacturing a solar cell module constituting a part of a battery module,
After coating the solder on substantially the entire surface of the electrode side of the solar cell element, the solar cell elements, superimposed on a surface of the side where the conductive pattern of the solar battery current collector sheet is formed, the solar then reflowed to comprising the step of heat-bonding the battery current collector sheet and the solar cell element,
The conductive pattern is composed of a plurality of conductive protrusions, and a non-conductive recess sharing the surface side of the resin base material as a bottom part and a wall surface of the conductive protrusion part as a side wall between the conductive protrusions,
Both side walls of the non-conductive recess have a reverse taper shape extending from the surface side of the resin base material ,
The angle formed between the bottom of the non-conductive recess and both side walls is in the range of 95 to 120 degrees;
The wiring width on the surface of the conductive convex portion is 0.2 mm to 5.0 mm, the width of the bottom portion of the nonconductive concave portion is 0.2 mm to 5.0 mm,
A predetermined thickness of the metal foil is 10 μm to 50 μm, and a step between the conductive convex portion and the non-conductive concave portion is 50 μm or less,
The solder seen contains a solder alloy and an epoxy resin,
The solder alloy moves onto the conductive convex portion when the heat bonding step is performed to form a conductive portion, and the epoxy resin is formed on the non-conductive concave portion when the heat bonding step is performed. A method for manufacturing a solar cell module, comprising filling and forming an insulating portion .

Images