JP4557770B2 - Method for manufacturing solar cell package and package - Google Patents

Description

  The present invention relates to a method for manufacturing a package of solar cells and the package.

  The solar cell module is produced by arranging a plurality of solar cells and connecting them. Therefore, it may be necessary to transport solar cells to the site where the solar cell module is manufactured. In such a case, solar cells can be efficiently transported by stacking and packing solar cells and transporting them.

  As a method of packing the stacked solar cells, a method of stacking, storing and packing the solar cells in a cardboard box or the like can be considered.

  However, in such a method, since the solar cell moves in the vertical direction and the horizontal direction in the cardboard box, there is a possibility that the solar cell may be damaged due to friction between the solar cells or an impact caused by vertical shaking.

  In patent document 1, in order to prevent such a damage, the method of surrounding the circumference | surroundings of the stacked photovoltaic cell with an air mat is proposed.

  However, in such a method, it is necessary to prepare an air mat for each box, which is complicated and expensive in terms of cost. Further, since an air mat is used, there is a problem that the volume increases and the transportation efficiency is poor.

The present inventor studied wrapping solar cells with a film or the like as a method for packing solar cells. However, when wrapped and packaged with a film, cracking or chipping may occur in the solar cells.
JP 2003-34363 A

  The objective of this invention is providing the manufacturing method and package of a photovoltaic cell package which can reduce that a deformation | transformation, damage, etc. generate | occur | produce in the case of packing and transportation.

  In the present invention, a first collector electrode for taking out the current generated in the cell by photoelectric conversion to the outside, and a second collector electrode for further collecting the current collected by the first collector electrode, Vertical direction in which solar cells formed on at least one of the front (front) surface and the back surface are stacked such that the first collector electrode and the second collector electrode extend in different directions. Is a method of manufacturing a package of solar cells by stacking a plurality of second collector electrodes so that the second collector electrodes almost overlap each other, and the film tightening strength along the direction parallel to the first collector electrodes, It is characterized by being weaker than the fastening strength of the film along the direction parallel to the second collector electrode.

  FIG. 3 is a plan view showing an example of the collector electrode formed on the surface of the solar battery cell. On the surface of the solar cell 3, a first collector electrode 1 extending in the lateral direction for taking out the current generated in the cell to the outside, and a second electrode extending in a direction substantially orthogonal to the first collector electrode 1. Current collector electrode 2 is formed. A collector electrode composed of relatively thin electrode fingers formed so as to extend from one end of the solar electrode cell to the other end and formed at a predetermined interval is generally called a finger-like electrode, and the first collector The electrode 1 corresponds to this finger-shaped electrode.

  The electrode for further collecting the current collected by the first collector electrode is generally called a bus bar, and the second collector electrode 2 extending in a direction substantially orthogonal to the first collector electrode 1 is the bus bar. It corresponds to. Therefore, the second collector electrode 2 is generally made of an electrode having a width wider than that of the first collector electrode 1 and is formed to have a height higher than that of the first collector electrode 1. . Moreover, the 1st collector electrode 1 and the 2nd collector electrode 2 are integrally formed.

  The thickness of the solar battery cell 3 is, for example, 50 to 400 μm, and an example is 180 μm. Moreover, the thickness of the electrode finger of the 1st collector electrode 1 is 15-90 micrometers, for example, and 45 micrometers is mentioned as an example. Moreover, the width | variety is 50-300 micrometers, for example, and 100 micrometers is mentioned as an example. The thickness of the 2nd collector electrode 2 is 20-140 micrometers, for example, and 70 micrometers is mentioned as an example. Moreover, the width | variety is 0.5-4 mm, for example, 2 mm is mentioned as an example.

  On the light receiving surface of the solar battery cell 3, the first collector electrode 1 and the second collector electrode 2 block the incident light to the solar battery cell 3, so that the area is preferably small. However, since the resistance loss increases when the area of the first collector electrode 1 is reduced, the thickness of the first collector electrode 1 is increased to increase the cross-sectional area. In addition, by providing a plurality of second collector electrodes 2, the traveling distance of current in the first collector electrode 1 is shortened. In many cases, two or more second collector electrodes 2 are usually provided, but one may be used.

  A first collector electrode and a second collector electrode similar to those on the front surface are provided on the back surface of the solar battery cell 3 of this example. However, some solar cells are provided with such a collector electrode only on one side. If the second collector electrode has a higher height (thickness) than the first collector electrode, The present invention can also be applied to such solar cells.

  When the solar cells 3 provided with the first collector electrode and the second collector electrode as shown in FIG. 3 are stacked, the state shown in FIGS. 4 and 5 is obtained. 4 and 5, since the height of the first collector electrode is lower than the height of the second collector electrode, only the second collector electrode is shown and the first collector electrode is not shown. . FIG. 4 is a side view seen from the direction A shown in FIG. As shown in FIG. 4, a plurality of solar cells 3 are stacked so that the second collector electrode 2 on the front surface of the solar cell 3 and the second collector electrode 2 on the back surface are in contact with each other. Since the second collector electrodes 2 are in contact with each other, the solar cells 3 are stacked without being in direct contact with each other. As shown in FIG. 4, a long distance exists between the end 3 a of the solar battery cell 3 and the second collector electrode 2. Accordingly, when an external stress is applied to the vicinity of the end 3a of the solar battery cell 3, the end 3a is greatly deformed by the external stress. For this reason, when a stress is applied from the outside during packing or transportation, there arises a problem that cracking or chipping occurs in the solar battery cell. In particular, single crystal silicon wafers used for solar cells are often ground and chamfered at corners, and stress is applied because microcracks are formed during such processing. In some cases, cracks and cracks are likely to occur.

  In the present embodiment, the height of the second collector electrode is higher than that of the first collector electrode. However, even if the heights of the first collector electrode and the second collector electrode are substantially the same, Even if the height of the first collector electrode is higher than that of the second collector electrode, the area of each electrode finger of the first collector electrode facing each other is small, so that the electrode fingers are displaced so as not to abut each other. Therefore, stress is applied to the vicinity of the end portion as described above with the second collector electrode having a large area as a fulcrum.

  FIG. 5 is a side view of the solar battery cell viewed from the direction B shown in FIG. As shown in FIG. 5, since the second collector electrode 2 extends in the left-right direction from one end to the other end, the distance from the end 2a of the second collector electrode 2 to the end 3a of the solar cell 3 Is getting shorter. Therefore, even if stress is applied to the end 3a of the solar battery cell, the amount of deformation is small. Accordingly, the solar cell 3 is not easily deformed when the film is wound along the direction parallel to the second collector electrode 2, and it is difficult to generate cracks and chips even when stress is applied along this direction. The inventor found out.

  The present invention is a method for manufacturing a package by covering stacked solar cells with a film, and relatively increasing the fastening strength of the film along the direction parallel to the second collector electrode. The tightening strength of the film along the direction parallel to is relatively weakened. As described above, in the winding of the film along the direction parallel to the first collector electrode, the end portion of the solar battery cell is easily deformed greatly. Therefore, by reducing the tightening strength of the film along this direction, Occurrence of burrs and the like can be reduced. As the film in the present invention, a film having a belt shape, a bag shape, or other shapes can be used.

  In the present invention, the band-like film is wound only along the direction parallel to the second collector electrode, so that the fastening strength of the film along the direction parallel to the first collector electrode is the direction parallel to the second collector electrode. The film may be weaker than the tightening strength of the film.

  In addition, the first strip film is wound along the direction parallel to the first collector electrode, and the second strip film is wound along the direction parallel to the second collector electrode. May be weaker than the fastening strength of the second belt-like film.

  In the present invention, a thermoplastic resin film such as a polyolefin film is preferably used as the film used for packing solar cells, and a heat shrink film that shrinks by heating is particularly preferably used.

  When using a heat-shrinkable film as the first band-shaped film and the second band-shaped film, the length of the first band-shaped film before heat shrinking is longer than the length of the second band-shaped film before heat-shrinking. Thus, the tightening strength of the first strip film may be weaker than the tightening strength of the second strip film.

  Moreover, you may use the film from which a thermal contraction rate differs by the 1st strip | belt-shaped film and the 2nd strip | belt-shaped film. In this case, a heat-shrinkable film having a relatively small heat shrinkage rate is used for the first band-shaped film, and a heat-shrinkable film having a relatively large heat shrinkage rate is used for the second band-shaped film. Thereby, the clamp | tightening intensity | strength of a 1st strip | belt-shaped film can be made weaker than a 2nd strip | belt-shaped film.

  The heat-shrinkable film is not particularly limited as long as it is a film that shrinks by heating, and examples thereof include a polyvinyl chloride film, a polypropylene film, a polyethylene film, a polystyrene film, a polyolefin film, and a polyethylene terephthalate film. .

  In another aspect according to the present invention, the stacked solar cells are covered with a heat shrink film in a bag shape, and packed by heating and shrinking. That is, it packs using the heat shrink film formed in the bag shape.

  When packing using a bag-shaped heat shrink film, for example, the peripheral length of the bag along the direction parallel to the first collector electrode is longer than the peripheral length of the bag along the direction parallel to the second collector electrode. By doing so, the fastening strength of the film along the direction parallel to the first collector electrode can be made weaker than the fastening strength of the film along the direction parallel to the second collector electrode.

  When a uniaxial heat-shrinkable film is used as the heat-shrinkable film, the direction of the heat-shrinkable film is arranged in a direction parallel to the second collector electrode so that an axial direction having a large heat shrinkage rate is along. Is preferred. Thereby, the clamping strength of the film along the direction parallel to the first collector electrode can be made weaker than the clamping strength of the film along the direction parallel to the second collector electrode.

  In a uniaxial heat-shrinkable film, the heat shrinkage rate in a predetermined axial direction is large, and the heat shrinkage rate is small in a direction substantially orthogonal to this direction. As the uniaxial heat shrink film, a polyvinyl chloride film, a polypropylene film, a polyethylene film, a polystyrene film, a polyethylene terephthalate film, and the like are known.

  Further, by controlling the heating method when shrinking the heat-shrinkable film, the tightening strength of the film along the direction parallel to the first collector electrode is more than the tightening strength of the film along the direction parallel to the second collector electrode. It may be weakened.

  Specifically, the temperature distribution when heating the film so that the thermal shrinkage is large along the direction parallel to the second collector electrode and the thermal shrinkage is small along the direction parallel to the first collector electrode. The method of controlling is mentioned. For example, when heat shrinking in a heating furnace, the temperature distribution in the heating furnace is controlled to be such a temperature distribution.

  In addition, in the case where the thermal contraction is performed by irradiating infrared rays, the thermal contraction is large along the direction parallel to the second electrode, and the thermal contraction is small along the direction parallel to the first collector electrode. Further, the film may be thermally shrunk by changing the irradiation time of infrared rays depending on the location of the film.

  The package of solar cells of the present invention is characterized by being manufactured by the manufacturing method of the present invention.

  In the above description, an example in which the first collector electrode and the second collector electrode extend substantially orthogonal to each other has been shown. However, in the present invention, the first collector electrode and the second collector electrode are in different directions. In other words, the first collector electrode and the second collector electrode may cross each other.

  ADVANTAGE OF THE INVENTION According to this invention, it can reduce that a deformation | transformation, damage, etc. generate | occur | produce in a photovoltaic cell in the case of packing, conveyance, etc.

  Moreover, since this invention covers and packs the stacked photovoltaic cells with a film, it can be packed easily and inexpensively.

  Further, since there is no significant increase in weight or volume at the time of packing, it can be efficiently transported.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to a following example.

Example 1
FIG. 1 is a perspective view showing a package of solar cells of one embodiment according to the present invention. As shown in FIG. 1, a plurality of stacked photovoltaic cells 3 are packed by winding a film 10. The film 10 is a belt-like film and is wound along a direction parallel to the second collector electrode 2. Since the film is not wound in the direction parallel to the first collector electrode 1, the tightening strength of the film along the direction parallel to the first collector electrode 1 is along the direction parallel to the second collector electrode 2. It is weaker than the tightening strength of the film.

  As the film 10, for example, a heat shrink film made of a polyolefin film or the like can be used.

  In this embodiment, the solar battery cell 3 includes an intrinsic i-type amorphous silicon thin film and a p-type or n-type amorphous silicon thin film on an n-type or p-type substantially rectangular single crystal silicon wafer. It is the solar cell deposited. The first collector electrode 1 and the second collector electrode 2 are formed by printing a conductive paste such as an Ag paste by screen printing or the like. However, the present invention is not limited to such a solar battery cell, and a solar battery cell using a single crystal silicon substrate having another structure, a polycrystalline solar battery cell, or a non-single crystal silicon thin film is used as a power generation layer. It can apply also to the photovoltaic cell etc. which were used as. The first collector electrode and the second collector electrode may also be formed by other methods.

FIG. 2 is a plan view showing a state before heat shrinkage when a heat shrink film is used as the film 10. 6 is a cross-sectional view taken along line AA in FIG. As shown in FIGS. 2 and 6, the film 10 is formed in an annular shape by thermally welding both ends of two heat-shrinkable films to form heat-welded portions 11 and 12. The annular film 10 is disposed around the stacked solar cells 3 and is wound around the stacked solar cells by heat shrinking the film 10 by heating. The width W _{1 of the} film 10 is preferably made narrower than the width W ₂ of the solar battery cell 3.

  In this embodiment, the film is wound using one film, but a plurality of films may be wound in the same direction. In such a case, it is preferable that each film is wound so as to cover at least one of the second collector electrodes 2. In the present invention, it is most preferable that the film is wound so as to cover all of the second collector electrode 2 as in this embodiment.

(Example 2)
FIG. 7: is a perspective view which shows the package of the photovoltaic cell of the other Example according to this invention. As shown in FIG. 7, the first strip film 30 is wound along the direction parallel to the first collector electrode 1, and the second strip film 20 is wound along the direction parallel to the second collector electrode 2. By winding, the stacked solar cells are packed. In the embodiment shown in FIG. 7, the fastening strength of the first belt-like film 30 is made weaker than the fastening strength of the second belt-like film 20. Therefore, the fastening strength of the film along the direction parallel to the first collector electrode 1 is made weaker than the fastening strength of the film along the direction parallel to the second collector electrode 2. By controlling the tightening strength of the first strip film 30 and the second strip film 20 in this way, it is possible to reduce the occurrence of chipping and cracking during the packing and transport of solar cells.

  FIG. 8 is a plan view showing a state before heat shrinkage when heat shrink films are used as the first belt film 30 and the second belt film 20 in the same manner as in the first embodiment. In the embodiment shown in FIG. 8, films having substantially the same degree of thermal shrinkage are used as the first belt-like film 30 and the second belt-like film 20. In order to make the fastening strength of the first belt-like film 30 weaker than that of the second belt-like film 20, in the embodiment shown in FIG. 8, the length (peripheral length) of the first belt-like film 30 is It is made longer than the length (peripheral length) of the strip-shaped film 20 of No. 2. For example, when the length of the 2nd strip | belt-shaped film 20 is set to 1, the length of the 1st strip | belt-shaped film 30 shall be about 1.1-2.

  The first belt-like film 30 and the second belt-like film 20 in a state before heat shrink as shown in FIG. 8 are heat shrunk by heating and wound around the stacked solar battery cells 3 and shown in FIG. The state is as follows.

Example 3
FIG. 9 is a plan view showing a solar cell packaging method according to still another embodiment of the present invention. In this embodiment, a bag-like film 40 is used as a film for packing the stacked solar battery cells 3. The bag-like film 40 is formed by stacking two heat-shrinkable films with the solar battery cell sandwiched therebetween, heat-welding the periphery thereof, and forming a heat-welded portion 41.

  10 is a cross-sectional view taken along line AA shown in FIG. In this embodiment, as shown in FIG. 9, the peripheral length of the bag along the direction parallel to the first electrode 1 is set to be longer than the peripheral length of the bag along the direction parallel to the second electrode 2. is doing. By increasing the peripheral length of the bag along the direction parallel to the first collector electrode 1, the fastening strength of the film along the direction parallel to the first electrode 1 can be increased in the direction parallel to the second collector electrode 2. It is weaker than the tightening strength of the film. The ratio of the peripheral length of the bag along the direction parallel to the first collector electrode 1 to the peripheral length of the bag along the direction parallel to the second collector electrode 2 is the same ratio as the ratio shown in Example 2 Can be mentioned.

(Example 4)
FIG. 11 is a plan view showing a method for packing solar battery cells according to still another embodiment of the present invention. Also in the present embodiment, a bag-like film is used as in the third embodiment. However, in this embodiment, instead of changing the peripheral length of the bag in the vertical and horizontal directions, a uniaxial heat-shrink film is used as the heat-shrink film, and the heat shrinks in a direction parallel to the second collector electrode 2. The direction of the heat-shrinkable film is arranged so that the axial direction with a high rate is along. Accordingly, the thermal contraction rate in the direction parallel to the second collector electrode 2 is larger than the thermal contraction rate in the direction parallel to the first collector electrode 1. For example, when the thermal contraction rate in the direction along the direction parallel to the first collector electrode 1 is 1, the thermal contraction rate in the direction along the direction parallel to the second collector electrode 2 is in the range of 1.1-10. It can be. In addition, also when using two strip | belt-shaped films shown in Example 2, using the film from which a thermal contraction rate differs, the fastening strength of a 1st strip | belt-shaped film is made weaker than the fastening strength of a 2nd strip | belt-shaped film. Also good.

(Example 5)
FIG. 12 is a plan view for explaining a method for packing solar battery cells according to still another embodiment of the present invention. In the present embodiment, the solar battery cells 3 are packed using a bag-like heat shrink film 60. The bag-shaped film 60 is formed into a bag shape by overlapping two heat shrink films and thermally welding the periphery to form a heat-welded portion 61.

  The heat shrinkage rate of the bag-like film 60 used in the present embodiment is a heat shrinkage film in which the heat shrinkage rates in the vertical direction and the horizontal direction are approximately the same. In the present embodiment, the degree of thermal contraction in the vertical direction and the case of thermal contraction in the horizontal direction are changed by changing the temperature distribution in the heating environment at the time of thermal contraction. Specifically, as shown in FIG. 12, infrared heaters 71 and 72 are arranged on both sides in the direction in which the second collector electrode 2 extends. Therefore, a region near the infrared heaters 71 and 72 of the bag-like film 60 is heated to a high temperature, and a region away from the infrared heaters 71 and 72 is heated at a lower temperature. As a result, heat shrinkage in the direction along the direction parallel to the second collector electrode 2 is relatively large, and heat shrinkage in the direction along the direction parallel to the first collector electrode 1 is relatively small. Therefore, the fastening strength of the film along the direction parallel to the first electrode 1 can be made weaker than the fastening strength of the film along the direction parallel to the second collector electrode 2.

  In the embodiment shown in FIG. 12, the arrangement of the infrared heaters 71 and 72 relatively weakens the film tightening strength along the direction parallel to the second collector electrode 2. By changing the time depending on the location of the film, the tightening strength of the film along the direction parallel to the second collector electrode 2 may be relatively weakened.

The perspective view which shows the package of the photovoltaic cell of one Example according to this invention. The top view which shows the packing method of the photovoltaic cell of one Example according to this invention. The top view which shows the 1st collector electrode and the 2nd collector electrode of the surface of a photovoltaic cell. The side view which looked at the photovoltaic cell stacked from the A direction shown in FIG. The side view which looked at the stacked photovoltaic cell from the B direction shown in FIG. Sectional drawing which follows the AA line shown in FIG. The perspective view which shows the package of the photovoltaic cell of the other Example according to this invention. The top view which shows the packing method of the photovoltaic cell of the other Example according to this invention. The top view for demonstrating the packaging method of the photovoltaic cell of the further another Example according to this invention. Sectional drawing in alignment with the AA shown in FIG. The top view for demonstrating the packaging method of the photovoltaic cell of the further another Example according to this invention. The top view for demonstrating the packaging method of the photovoltaic cell of the further another Example according to this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... 1st collector electrode 2 ... 2nd collector electrode 2a ... End part of 2nd collector electrode 3 ... Solar cell 3a ... End part of photovoltaic cell 10 ... Strip-shaped film 20 ... Second strip-shaped film 30 ... First belt-like film 40 ... bag-like heat shrink film 50 ... bag-like heat shrink film 60 ... bag-like heat shrink film 71, 72 ... infrared heater

Claims (13)

A first collector electrode for taking out the current generated in the cell by photoelectric conversion to the outside and a second collector electrode for further collecting the current collected by the first collector electrode are a table of the cells (front ) Solar cells that are formed on at least one of the surface and the back surface so that the first collector electrode and the second collector electrode extend in different directions are stacked in the vertical direction. A method of manufacturing a package of solar cells by stacking a plurality of second collector electrodes so that they substantially overlap each other and covering with a film,
A package for a solar cell, wherein the tightening strength of the film along the direction parallel to the first collector electrode is made weaker than the tightening strength of the film along the direction parallel to the second collector electrode. Production method.   By winding the belt-like film only along the direction parallel to the second collector electrode, the fastening strength of the film along the direction parallel to the first collector electrode is increased in the direction parallel to the second collector electrode. The manufacturing method of the package of the photovoltaic cell of Claim 1 made weaker than the fastening strength of the film which follows.   The first strip film is wound along a direction parallel to the first collector electrode, the second strip film is wound along a direction parallel to the second collector electrode, and the first strip film is tightened. The method for manufacturing a package of solar cells according to claim 1, wherein the strength is weaker than the fastening strength of the second strip-shaped film.   A heat-shrinkable film is used as the first band-shaped film and the second band-shaped film, and the length of the first band-shaped film before heat shrinking is made longer than the length of the second band-shaped film before heat-shrinking. The manufacturing method of the package of the photovoltaic cell of Claim 3 characterized by making the fastening strength of a said 1st strip | belt-shaped film weaker than the fastening strength of a said 2nd strip | belt-shaped film.   Using a heat shrink film as the first belt film and the second belt film, using a heat shrink film having a relatively small heat shrinkage ratio as the first belt film with respect to the second belt film, By using a heat-shrinkable film having a relatively high thermal shrinkage rate as compared with the first band-shaped film as the second band-shaped film, the tightening strength of the first band-shaped film can be increased by tightening the second band-shaped film. The manufacturing method of the package of the photovoltaic cell of Claim 3 made weaker than intensity | strength.   The method for producing a packaged solar cell according to claim 1, wherein the stacked solar cells are covered with a heat shrink film in a bag shape and then packed by heating and shrinking.   A direction parallel to the first collector electrode by making the peripheral length of the bag along the direction parallel to the first collector electrode longer than the peripheral length of the bag along the direction parallel to the second collector electrode The method of manufacturing a package according to claim 6, wherein the tightening strength of the film along the direction is made weaker than the tightening strength of the film along the direction parallel to the second collector electrode.   A uniaxial heat-shrinkable film is used as the heat-shrinkable film, and the direction of the heat-shrinkable film is arranged so that the axial direction having a large heat shrinkage rate is along the direction parallel to the second collector electrode. 7. The solar cell package according to claim 6, wherein the fastening strength of the film along the direction parallel to the collector electrode is made weaker than the fastening strength of the film along the direction parallel to the second collector electrode. Manufacturing method.   Control the temperature distribution when heating the film so that the heat shrinkage is large along the direction parallel to the second collector electrode and the heat shrinkage is reduced along the direction parallel to the first collector electrode. The manufacturing method of the package of the photovoltaic cell of Claim 6 characterized by the above-mentioned.   The infrared irradiation time is changed depending on the film location so that the heat shrinkage is large along the direction parallel to the second collector electrode and the heat shrinkage is reduced along the direction parallel to the first collector electrode. The method of manufacturing a package of solar cells according to claim 6, wherein the film is thermally contracted.   These heat-shrinkable films are used as the first belt-like film and the second belt-like film, so that the heat-shrinkage rate of the second belt-like film is large and the heat-shrinkage rate of the first belt-like film is small. The method for producing a package of solar cells according to claim 3, wherein a temperature distribution at the time of heating the film is controlled.   An infrared ray is used so that a heat shrink film is used as the first belt film and the second belt film, the heat shrink rate of the second belt film is large, and the heat shrink rate of the first belt film is small. The method for producing a package of solar cells according to claim 3, wherein the film is thermally shrunk by changing the irradiation time of the film according to the location of the film. A package of solar cells produced by the method according to any one of claims 1 to 12.