JP4666405B2 - Manufacturing method of solar cell - Google Patents

Description

The present invention covers a solar cell element that photoelectrically converts sunlight collected by a condenser lens, a resin sealing portion that resin-seals the solar cell element, and a surface of the resin sealing portion that faces the condenser lens method for manufacturing a solar cell and a light-transmitting covering plate for about.

  As a solar power generation device, a non-condensing fixed type flat plate structure in which a solar power generation module configured by laying solar cell elements without gaps is installed on a roof or the like is common. However, since a large number of processing steps and high processing accuracy are required, a large amount of expensive solar cell elements are required, and the entire photovoltaic power generation module is very expensive.

  Then, the concentrating solar power generation module which concentrates sunlight and irradiates sunlight to the solar cell element comprised by the small area is proposed (for example, refer patent document 1 and patent document 2). That is, it is intended to provide a more inexpensive solar power generation device by configuring an expensive solar cell element with a small area.

  In the concentrating solar power generation device (solar cell, solar cell module) disclosed in Patent Document 1, light shielding for shielding the transparent resin interposed on the light receiving surface of the solar cell (solar cell element) from sunlight. It is said that a concentrating solar power generation device with no deterioration of light and improved durability can be provided by providing a member.

  However, in the concentrating solar power generation device, the energy density of sunlight collected on the light receiving surface of the solar battery cell is increased for that purpose, and the energy condensed on the light receiving surface becomes heat and becomes transparent resin. There is a concern that air bubbles are accumulated in the transparent resin.

  If air bubbles are generated once, a part of the sunlight condensed on the light receiving surface of the solar battery cell is scattered or reflected by the air bubbles, and the surface of the solar battery cell is not normally irradiated. That is, with the generation of bubbles, there is a risk that the photoelectric conversion efficiency of the concentrating solar power generation device (solar battery cell) is lowered and the generated power generated is reduced.

  Moreover, in the concentrating solar power generation device (solar cell, solar cell module) disclosed in Patent Document 2, a photovoltaic element (solar cell element) is obtained by using a thermally conductive sealing material containing a filler. It is disclosed that heat dissipation is improved to prevent a temperature rise and a reduction in conversion light rate of the photovoltaic element is prevented.

However, since the filler is mixed in the sealing material, the condensed light is absorbed through the filler depending on the light collecting conditions, and as a result, heat may be accumulated in the sealing material. May cause similar problems.
JP 2006-313809 A Japanese Patent Laid-Open No. 2003-69068

This invention is made | formed in view of such a condition, The resin sealing part which resin-seals the solar cell element which photoelectrically converts the condensed sunlight, and the translucency which coat | covers the resin sealing part A method of manufacturing a solar cell comprising a covering plate, wherein a plurality of surface sealing thicknesses, which are thicknesses of resin sealing portions between the surface of the solar cell element and the light-transmitting covering plate, are made different. A sample preparation step for preparing a sample, an acceleration test step for measuring a foaming time during which bubbles are generated by performing an acceleration test on the sample, and obtaining a foaming characteristic curve representing a relationship of the foaming time to the surface sealing thickness, and It was by providing a sealing thickness defining step of defining a defining surface sealing thickness of the foam to suppress the thickness of the sealing resin in the resin sealing portion from foaming characteristics curve by sunlight, solar To reduce the effects of the bubbles and suppress the generation of bubbles in the resin sealing part, And to provide a method for manufacturing a solar cell can be manufactured with good productivity solar cells with high reliability capable of preventing reduction in photoelectric conversion efficiency due to generation of foam.

  Moreover, this invention is a manufacturing method of a solar cell provided with the resin sealing part which resin-seals the solar cell element which photoelectrically converts the condensed sunlight, and the translucent coating plate which coat | covers the resin sealing part. A solar cell element placing step for placing a solar cell element on a receiver substrate, a translucent covering plate arranging step for arranging a translucent covering plate, and a resin sealing portion for forming a resin sealing portion And forming a surface sealing thickness, which is the thickness of the resin sealing portion between the surface of the solar cell element and the light transmitting covering plate, in the light transmitting cover plate arranging step. A highly reliable solar cell in which a foaming phenomenon does not occur in a resin-encapsulated portion due to secular change by disposing a translucent covering plate so as to be thinner than a demarcated surface sealing thickness defined by the solar cell manufacturing method. To provide a solar cell manufacturing method that enables easy and high-precision production For the purpose of.

A method for manufacturing a solar cell according to the present invention includes a solar cell element that photoelectrically converts sunlight collected by a condenser lens, a receiver substrate on which the solar cell element is placed, and a resin-sealed solar cell element. A solar cell manufacturing method comprising: a resin sealing portion to be stopped; and a translucent covering plate that covers a surface of the resin sealing portion on the condenser lens side, the surface of the solar cell element and the transparent A sample preparation step of preparing a plurality of samples having different surface sealing thicknesses, which is the thickness of the resin sealing portion, with the optical coating plate, and bubbles are generated by performing an acceleration test on the samples. Measure the foaming time to be generated, and the acceleration test step for obtaining the foaming characteristic curve representing the relation of the foaming time to the surface sealing thickness, and foaming from the sealing resin at the resin sealing part by the concentrated sunlight Depressing surface sealing thickness as a thickness to suppress the foaming Characterized in that it comprises a sealing thickness defining step of defining the sexual curve.

With this configuration, the foaming from the sealing resin that is affected by the irradiation of the concentrated sunlight by defining the surface sealing thickness as a thickness that suppresses foaming from the sealing resin with ease and high accuracy Therefore, a highly reliable solar cell that reduces the influence of sunlight, suppresses the generation of bubbles in the resin sealing portion, and prevents the decrease in photoelectric conversion efficiency due to the generation of bubbles. It can be manufactured with high productivity .

  Moreover, the manufacturing method of the solar cell according to the present invention includes a solar cell element that photoelectrically converts sunlight condensed by a condenser lens, a receiver substrate on which the solar cell element is placed, and the solar cell element. A method for manufacturing a solar cell comprising: a resin sealing portion that is resin-sealed; and a translucent covering plate that covers a surface of the resin sealing portion on the condenser lens side, wherein the solar cell is provided on the receiver substrate. A solar cell element placing step for placing an element, a translucent covering plate placing step for placing the translucent covering plate, and a resin sealing portion forming step for forming the resin sealing portion, In the translucent covering plate arrangement step, the surface sealing thickness, which is the thickness of the resin sealing portion between the surface of the solar cell element and the translucent covering plate, is determined according to the present invention. The translucent coating so as to be thinner than the defined surface sealing thickness defined by the battery manufacturing method Characterized by arranging the.

  With this configuration, it is possible to easily and accurately produce a highly reliable solar cell that does not cause a foaming phenomenon at the resin sealing portion due to aging.

  In the method for manufacturing a solar cell according to the present invention, the translucent coating plate is disposed before the translucent coating plate arranging step, and the surface sealing thickness is smaller than the demarcated surface sealing thickness. A sealing frame forming step of forming a sealing frame to be determined on the receiver substrate in correspondence with an end of the resin sealing portion.

  With this configuration, it is possible to determine the surface sealing thickness with a sealing frame in which the translucent cover plate is arranged with a high accuracy to a thickness thinner than the demarcated surface sealing thickness, thus suppressing the foaming phenomenon. It becomes possible to manufacture the solar cell easily and with high accuracy.

According to the method for manufacturing a solar cell according to the present invention, a solar cell element that photoelectrically converts sunlight collected by a condenser lens, a receiver substrate on which the solar cell element is placed, and a solar cell element are sealed with resin. A solar cell manufacturing method comprising: a resin sealing portion to be stopped; and a translucent covering plate that covers a surface of the resin sealing portion on the side of the condenser lens, the surface of the solar cell element and the translucent covering plate The sample preparation process for preparing multiple samples with different surface sealing thicknesses, which is the thickness of the resin sealing part, and the foaming time during which bubbles are generated by performing an accelerated test on the sample are measured. Accelerated test process for obtaining a foaming characteristic curve representing the relationship of foaming time to surface sealing thickness, and a demarcated surface as a thickness that suppresses foaming from the sealing resin at the resin sealing part due to concentrated sunlight A sealing thickness defining step for defining the sealing thickness from the foam characteristic curve; Since comprise, foaming from the sealing resin affected by irradiation of sunlight focused to define a defining surface sealing thickness as the thickness of suppressing foaming of the sealing resin easily and accurately Therefore, a highly reliable solar cell that reduces the influence of sunlight, suppresses the generation of bubbles in the resin sealing portion, and prevents the decrease in photoelectric conversion efficiency due to the generation of bubbles. There exists an effect that it can manufacture with sufficient productivity .

  Moreover, according to the method for manufacturing a solar cell according to the present invention, a solar cell element that photoelectrically converts sunlight collected by a condenser lens, a receiver substrate on which the solar cell element is placed, and a solar cell element A method for manufacturing a solar cell comprising a resin sealing portion to be resin-sealed and a translucent covering plate that covers a surface of the resin sealing portion on the side of the condenser lens, wherein the solar cell element is placed on a receiver substrate A solar cell element mounting step, a translucent coating plate arranging step for arranging a translucent coating plate, and a resin sealing portion forming step for forming a resin sealing portion, and a translucent coating plate arranging step Then, the surface sealing thickness, which is the thickness of the resin sealing portion between the surface of the solar cell element and the translucent covering plate, is defined surface sealing defined by the solar cell manufacturing method according to the present invention. Since the translucent cover plate is placed so as to be thinner than the thickness, the resin sealing part due to secular change And a solar cell having high reliability foaming phenomenon does not occur easily an effect that it becomes possible to produce high precision.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<Embodiment 1>
Based on FIG. 1A and FIG. 1B, the solar cell and the concentrating solar power generation module according to the present embodiment will be described.

  FIG. 1A is a cross-sectional view showing a schematic configuration of the solar cell and the concentrating solar power generation module according to Embodiment 1 of the present invention.

  FIG. 1B is a plan view showing the solar cell shown in FIG. 1A as viewed from the condenser lens side. In addition, arrow AA shown to FIG. 1B is corresponded in the cross-sectional position of FIG. 1A.

  Solar cell 10 according to the present embodiment has sunlight Ls collected by condenser lens 42 (sunlight Lsf collected by condenser lens 42 toward the surface of solar cell element 11. When it is not necessary to distinguish the sunlight Lsf, it is simply referred to as sunlight Ls.) The solar cell element 11 for photoelectric conversion, the receiver substrate 20 on which the solar cell element 11 is placed, and the solar cell element 11 are made of resin. A resin sealing portion 33 to be sealed and a translucent covering plate 32 that covers the surface of the resin sealing portion 33 on the condenser lens 42 side are provided.

  Further, in the solar cell 10, the surface sealing thickness Tsr that is the thickness of the resin sealing portion 33 between the surface of the solar cell element 11 and the translucent coating plate 32 is the concentrated sunlight Ls. (Sunlight Lsf. Hereinafter, when there is no particular need to distinguish sunlight Lsf, it is simply referred to as sunlight Ls.) Is defined as a thickness that suppresses foaming from the sealing resin at the resin sealing portion 33. The demarcated surface sealing thickness DTsr (see the second embodiment) is made thinner.

  Therefore, the surface sealing thickness Tsr is formed to be thinner than the defined surface sealing thickness DTsr defined as the thickness for suppressing foaming from the sealing resin, and the sealing is affected by the irradiation of the concentrated sunlight Lsf. Since the amount of the stopping resin can be suppressed, the influence of the sunlight Lsf is reduced to suppress the generation of bubbles in the resin sealing portion, and the reliability in which the photoelectric conversion efficiency is prevented from being lowered due to the generation of bubbles. High solar cell 10.

  In the solar cell 10, the sealing frame 31 formed between the receiver substrate 20 and the light-transmitting cover plate 32 and defining the surface sealing thickness Tsr to be thinner than the delimiting surface sealing thickness DTsr is resin-sealed. Provided at the end of the portion 33.

  Therefore, it is possible to easily and accurately set the parallel distance (surface sealing thickness Tsr) between the surface of the solar cell element 11 and the translucent covering plate 32 to be smaller than the defined surface sealing thickness DTsr. Thus, foaming can be prevented over a long period of time, and a highly reliable solar cell 10 can be obtained.

  In the present embodiment, the sealing resin is a silicone resin, and the defined surface sealing thickness DTsr is 0.8 mm. Therefore, since the surface sealing thickness Tsr in the resin sealing portion 33 made of silicone resin can be limited to 0.8 mm or less, from the start of operation to the generation of bubbles by the concentrated sunlight Ls. It is possible to reliably extend the foaming time Tvg of the solar cell 10 with high reliability.

  The reason why the defined surface sealing thickness DTsr is set to 0.8 mm will be further described in the second embodiment. The height Hf of the sealing frame 31 is a value obtained by adding the chip thickness of the solar cell element 11 to the surface sealing thickness Tsr.

  The solar cell 10 according to the present embodiment can be applied as the concentrating solar power generation module 40 as it is. That is, the concentrating solar power generation module 40 according to the present embodiment has the sunlight Ls (sunlight Lsv incident in the vertical direction with respect to the concentrating solar power generation module 40. Hereinafter, the solar light Lsv is particularly distinguished. When it is not necessary to perform this, it is simply referred to as sunlight Ls.) A condensing lens 42 for condensing light, and a solar cell 10 for photoelectrically converting sunlight Ls (sunlight Lsf) collected by the condensing lens 42 Is provided.

  Therefore, generation | occurrence | production of the bubble in the resin sealing part 33 resulting from long-term operation | movement (irradiation of the sunlight Lsf which is condensed and has high-density ultraviolet rays) is suppressed, and the photoelectric conversion efficiency fall by generation | occurrence | production of a bubble is suppressed. It can be set as the reliable concentrating solar power generation module 40 prevented.

  The solar cell element 11 is made of, for example, a semiconductor material that is any one of Si, GaAs, InGaP, AlInGaAs, AlGaAs, InGaAs, InGaAsN, Ge, CuInGaSe, and CdTe, or a combination thereof. Therefore, it is possible to configure the solar cell element for high magnification condensing by applying an inorganic material such as a group IV semiconductor, a group III-V compound semiconductor, or a group II-VI compound semiconductor.

  Moreover, the structure of the solar cell element 11 can be applied in various forms such as a single-junction cell, a monolithic multi-junction cell, or a mechanical stack type in which various solar cells having different wavelength sensitivity regions are connected. It is.

  Note that the outer size of the solar cell element 11 is preferably about several mm to about 20 mm from the viewpoints of reduction of solar cell materials to be used, ease of processing, ease of process, simplification, and the like. In the present embodiment, the outer size of the solar cell element 11 is 8 mm square.

  The receiver substrate 20 has a desired wiring (solar wiring) via a suitable insulating layer on a base base made of a metal such as an aluminum plate or a copper plate or a ceramic such as aluminum nitride, silicon nitride, or silicon carbide. A connection pattern that is connected to the electrode (not shown) of the battery element 11 and is taken out to the outside, and a connection pattern for connecting the solar cells 10 in series or in parallel (not shown) is formed. . In the present embodiment, the receiver substrate 20 has a 60 mm square and a thickness of 2. mm. A mm aluminum plate was used.

  The current generated by the solar cell element 11 is appropriately taken out of the solar cell 10 by wiring formed on the receiver substrate 20. Since the wiring formed on the receiver substrate 20 needs to ensure highly reliable insulation, for example, a connection pattern formed of copper foil is insulated by covering it with an insulating film such as an organic material. is there.

The translucent covering plate 32 is made of, for example, a heat-resistant glass plate, and ensures heat resistance and moisture resistance to improve weather resistance. Further, the thickness of the translucent cover plate 32 is set to be able to secure heat resistance by suppressing the irradiation intensity of sunlight Lsb on the surface on the condenser lens 42 side, for example, about 0.35 kW / m ² or less. . In this embodiment, it is about 5 mm to 7.5 mm. Moreover, the translucent covering plate 32 was made of borosilicate glass having high heat resistance and low coefficient of thermal expansion.

  Moreover, the resin sealing part 33 is comprised with the insulating resin (sealing resin) with which it filled between the solar cell element 11 and the translucent coating board 32, for example, transparent silicone resin (transparency as high as possible) It is preferable that the solar cell element 11 is irradiated with sunlight Ls that has passed through the translucent cover plate 32.

  The condensing lens 42 is configured to face the sun by the action of a tracking mechanism (not shown). Therefore, the sunlight Ls is incident as sunlight Lsv in a direction perpendicular to the incident surface of the condenser lens 42 (a direction parallel to the optical axis Lax of the optical system). The condensing lens 42 is configured to condense sunlight Lsf refracted from sunlight Lsv onto the solar cell element 11.

  As the solar cell element 11 applied to the concentrating solar power generation module 40, since high efficiency and practicality are particularly required, a three-junction solar cell element composed of InGaP / GaAs / Ge, AlGaAs / It is desirable to use a solar cell element made of Si or a monolithic multi-junction solar cell element.

  In order to effectively collect light by the condensing lens 42, the surface of the solar cell element 11 that photoelectrically converts sunlight Ls is the incident surface of the condensing lens 42, the incident surface of the translucent cover plate 32, and the exit surface. Are arranged in parallel.

  Examples of the condenser lens 42 include a biconvex lens, a plano-convex lens, and a Fresnel lens. From the viewpoint of weight, cost, ease of handling in the usage environment, etc., the incident surface that receives sunlight Ls (sunlight Lsv) is flat, and the solar cell element 11 is irradiated with sunlight Ls (sunlight Lsb). It is desirable that the surface has a Fresnel lens shape having a substantially triangular cross section.

  As a material of the condensing lens 42, the thing with the high transmittance | permeability with the sensitivity wavelength light of the solar cell element 11 and a weather resistance is good. For example, it is possible to apply white plate tempered glass, weather resistant grade acrylic, polycarbonate, and the like that are generally used for ordinary solar cell modules (solar power generation systems) and the like. In addition, the material of the condensing lens 42 is not limited to these, You may make these materials into the multilayer structure. In addition, an appropriate ultraviolet absorber can be added to these materials for the purpose of preventing ultraviolet degradation of the condenser lens 42 itself and other members.

<Embodiment 2>
A method for manufacturing the solar cell 10 according to the first embodiment (particularly, a method for defining the defined surface sealing thickness DTsr) will be described as a second embodiment with reference to FIGS. The reference numerals of the solar cell 10 described in the first embodiment are used, and different items are mainly described.

  FIG. 2 is a schematic diagram showing a schematic configuration of an acceleration test for obtaining a foaming characteristic curve in the method for manufacturing a solar cell according to Embodiment 2 of the present invention.

  FIG. 3 is a flowchart showing a processing flow when the defined surface sealing thickness is obtained by the acceleration test shown in FIG.

  FIG. 4 is an explanatory diagram showing foaming characteristics obtained by the acceleration test shown in FIG. 2, (A) is a characteristic chart showing measured values of foaming time with respect to the surface sealing thickness, and (B) is (A). It is the characteristic graph which calculated | required the foaming characteristic curve from the measured value of.

  The present embodiment is a method for manufacturing the solar cell 10, and obtains the foaming characteristic curve CC (FIG. 4B) by an acceleration test (FIG. 2) to which the solar simulator SS is applied. The defined surface sealing thickness DTsr that defines the upper limit of the thickness Tsr is obtained based on the foaming characteristic curve CC.

  The acceleration test was performed, for example, by emitting a xenon lamp to collect light to generate pseudo sunlight Lsf and irradiating the solar cell 10 with the sunlight Lsf from the solar simulator SS. The concentration factor of sunlight Lsf was set to about 1300 times. In addition, the magnitude | size of a condensing magnification is the value converted from the electric current which the solar cell 10 generate | occur | produced. In addition, the solar cell 10 was placed on the Peltier element PLTD set at a temperature of 60 ° via heat dissipating grease to ensure the stability of the operating conditions of the solar cell 10.

  As described above, the solar cell that is the target of the manufacturing method according to the present embodiment is the other solar cell 10 described in the first embodiment. That is, the solar cell 10 includes resin-sealing the solar cell element 11 that photoelectrically converts sunlight Ls collected by the condenser lens 42, the receiver substrate 20 on which the solar cell element 11 is placed, and the solar cell element 11. The resin sealing part 33 which stops and the translucent coating | coated board 32 which coat | covers the surface at the side of the condensing lens 42 of the resin sealing part 33 are provided.

  A method for manufacturing solar cell 10 according to the present embodiment (a method for defining defined surface sealing thickness DTsr) includes a processing flow (FIG. 3) of steps S1 to S3.

Step S1:
A plurality of samples (solar cells 10) are prepared in which the surface sealing thickness Tsr, which is the thickness of the resin sealing portion 33 between the surface of the solar cell element 11 and the translucent covering plate 32, is different (see FIG. Sample preparation process).

  In the present embodiment, the surface sealing thickness Tsr is, for example, four types of 0.3 mm, 0.6 mm, 1.0 mm, and 1.25 mm.

Step S2:
The sample is subjected to an acceleration test (irradiation of solar light Lsf from the solar simulator SS) to measure a foaming time Tvg in which bubbles are generated, and a foaming characteristic curve CC representing the relationship of the foaming time Tvg to the surface sealing thickness Tsr is obtained ( Accelerated test process). The occurrence of the foaming phenomenon can be detected by a change in operating current.

  The measured values obtained by the acceleration test are as shown in FIG. Specifically, when the surface sealing thickness Tsr = 0.3 mm, the foaming time Tvg = 86,400 sec. When the surface sealing thickness Tsr = 0.6 mm, the foaming time Tvg = 32,400 sec. When the thickness Tsr = 1.0 mm, the foaming time Tvg = 8,100 to 6,000 sec. When the surface sealing thickness Tsr = 1.25 mm, the foaming time Tvg = 2,400 to 2,700 sec.

  Foaming characteristics indicating the relationship of the foaming time Tvg to the surface sealing thickness Tsr by graphing the measured values with the horizontal axis as the surface sealing thickness Tsr (mm) and the vertical axis as the foaming time Tvg (sec). A curve CC is obtained (FIG. 4B). That is, the foaming characteristic curve CC can be obtained as a curve of a characteristic graph representing the relationship of the foaming time Tvg (for example, the vertical axis) to the surface sealing thickness Tsr (for example, the horizontal axis).

  That is, the foaming characteristic curve CC has a characteristic that the foaming time Tvg becomes shorter as the surface sealing thickness Tsr becomes larger, and is a decreasing curve that gradually decreases exponentially.

  From the foaming characteristic curve CC, it can be seen that the foaming time Tvg varies greatly depending on the surface sealing thickness Tsr. For example, as described above, when the surface sealing thickness Tsr = 1.0 mm, the foaming time Tvg = 8,100 to 6,000 sec. When the surface sealing thickness Tsr = 0.6 mm, the foaming time Tvg = 32, 400 seconds. Therefore, the foaming time Tvg can be prolonged by about 4 to 5 times by changing the surface sealing thickness Tsr from 1.0 mm to 0.6 mm.

  Therefore, it is considered that the cause of the bubble generation is the presence of the resin sealing portion 33 as will be described later, and that the sealing resin of the resin sealing portion 33 is altered by irradiation with sunlight Ls.

Step S3:
The demarcated surface sealing thickness DTsr as a thickness for suppressing foaming from the sealing resin at the resin sealing portion 33 by the concentrated sunlight Ls is defined from the foaming characteristic curve CC (sealing thickness defining step) ).

  As described above, since the foaming characteristic curve CC is a decreasing curve that decreases exponentially, the required foaming time Tvg is determined by setting the definitive surface sealing thickness DTsr as the upper limit of the surface sealing thickness Tsr. It can be realized easily and reliably.

  In the present embodiment, by providing a sample preparation step, an acceleration test step, and a sealing thickness defining step, the defined surface sealing thickness DTsr as a thickness for suppressing foaming from the sealing resin can be easily and highly accurate. Therefore, it is possible to suppress foaming from the sealing resin due to the irradiation of the sunlight Ls that has been defined and condensed, so that the generation of bubbles in the resin sealing portion 33 is suppressed, and photoelectric conversion due to the generation of bubbles is performed. A highly reliable solar cell 10 that prevents a decrease in efficiency can be manufactured with high productivity.

  The defined surface sealing thickness DTsr can be defined as follows, for example.

  In the present embodiment, the definition of the defined surface sealing thickness DTsr in the sealing thickness defining step is performed by extracting the tangential inclination angle θc with respect to the foaming characteristic curve CC and setting the thickness at which the tangential inclination angle θc is 45 degrees. This is done by defining a definitive surface sealing thickness DTsr. With this configuration, the demarcated surface sealing thickness DTsr can be specified easily and with high accuracy, and thus a highly reliable solar cell 10 can be manufactured with high productivity.

  That is, in the foaming characteristic curve CC, the tangential slope angle θc is 45 degrees or more in the range where the surface sealing thickness Tsr is not more than the defined surface sealing thickness DTsr with the defined surface sealing thickness DTsr as a boundary, and the foaming time Tvg Can be easily prolonged. On the other hand, when the surface sealing thickness Tsr exceeds the defined surface sealing thickness DTsr, the tangential inclination angle θc is 45 degrees or less, and the foaming time Tvg is larger than the foaming time Tvg when the defined surface sealing thickness DTsr. Becomes shorter and the foaming phenomenon tends to occur.

  In the method for manufacturing solar cell 10 according to the present embodiment, demarcated surface sealing thickness DTsr for solar cell 10 is equal to surface sealing thickness Tsr when tangential inclination angle θc with respect to foaming characteristic curve CC is 45 degrees. Has been. Therefore, the definitive surface sealing thickness DTsr as the upper limit of the surface sealing thickness Tsr can be specified easily and with high accuracy, and therefore the surface sealing thickness Tsr can be easily set with high accuracy (formation). Thus, the highly reliable solar cell 10 can be easily manufactured.

  In the present embodiment, the sealing resin of the resin sealing portion 33 is a silicone resin, and in the case of a silicone resin, the contact angle of inclination θc is expressed by a foaming characteristic curve CC representing the relationship between the surface sealing thickness Tsr and the foaming time Tvg. The surface sealing thickness Tsr when the angle is 45 degrees is determined as about 0.8 mm (FIG. 4B). That is, the defined surface sealing thickness DTsr can be defined as about 0.8 mm.

  In the foam characteristic curve CC, when the surface sealing thickness Tsr is 0.8 mm or less, the tangential inclination angle θc is 45 degrees or more, and when the surface sealing thickness Tsr exceeds 0.8 mm, the tangential inclination angle θc is less than 45 degrees. Therefore, by setting the surface sealing thickness Tsr to 0.8 mm (defined surface sealing thickness DTsr) or less, the foaming time is compared with the case where the surface sealing thickness Tsr exceeds 0.8 mm. Tvg can be greatly improved (lengthened), and the reliability of the solar cell 10 can be improved.

  As described above, the defined surface seal thickness DTsr can be defined as 0.8 mm. That is, by setting the surface sealing thickness Tsr to 0.8 mm (defined surface sealing thickness DTsr) or less, it becomes possible to prolong the foaming time Tvg to obtain a highly reliable solar cell 10.

  The lower limit of the surface sealing thickness Tsr is that it is possible to prevent entrainment of bubbles in the sealing resin when the resin sealing portion 33 is formed, and the wire to the surface electrode of the solar cell element 11. It is possible to determine in consideration of mounting restrictions such as providing a connection margin of (connection member) and ensuring the reliability of the sealing action of the resin sealing portion 33. For example, these conditions can be satisfied by setting the surface sealing thickness Tsr = 0.1 mm or more.

  The cause of the foaming phenomenon is due to the temperature rise due to light absorption of the sealing resin (resin sealing portion 33) due to the irradiation of the concentrated sunlight Ls, and the thermal decomposition of the sealing resin due to the temperature rise of the solar cell element 11, It is considered that the main chain of the chain polymer of the encapsulating resin is cut and the molecular weight is lowered and gasified.

  Therefore, as described above, the upper limit of the surface sealing thickness Tsr is preferably set to the demarcated surface sealing thickness DTsr. That is, by forming the surface sealing thickness Tsr thinner than the demarcated surface sealing thickness DTsr, the ultraviolet light absorbed by the resin sealing portion 33 is reduced, and the thermal energy accumulated in the resin sealing portion 33 is reduced. It is possible to suppress the decomposition of the sealing resin due to the irradiation of sunlight Ls, and the foaming time Tvg can be prolonged.

  Further, the lower limit of the surface sealing thickness Tsr does not exist from the viewpoint of the foaming phenomenon, but is necessary from the viewpoint of the surface protection (humidity resistance, weather resistance, mechanical stability, etc.) of the solar cell element 11, and is described above. It is preferable to define in consideration of the mounting restrictions.

<Embodiment 3>
Next, the manufacturing method of the solar cell which manufactures the solar cell 10 is demonstrated.

  This embodiment is a method for manufacturing solar cell 10 described in Embodiments 1 and 2 (particularly, manufacturing of solar cell 10 to which the definitive surface sealing thickness DTsr defined in Embodiment 2 is applied). Method) will be described as a third embodiment. Mainly different matters will be described using the reference numerals of the solar cell 10 described in the first embodiment and the second embodiment.

  FIG. 5 is a flowchart showing a processing flow in the solar cell manufacturing method according to Embodiment 3 of the present invention.

  The method for manufacturing solar cell 10 according to the present embodiment includes the processing flow of steps S11 to S14.

  As described above, the solar cell 10 includes the solar cell element 11 that photoelectrically converts the sunlight Ls collected by the condenser lens 42, the receiver substrate 20 on which the solar cell element 11 is placed, and the solar cell element 11. A resin sealing portion 33 for sealing with resin and a translucent covering plate 32 for covering the surface of the resin sealing portion 33 on the condenser lens 42 side are provided.

Step S11:
First, the solar cell element 11 is bonded and placed on the receiver substrate 20 by die bonding (solar cell element placing step). An electrode (not shown) of the solar cell element 11 is connected to a wiring (not shown) formed on the receiver substrate 20 by wire bonding (not shown).

Step S12:
Next, the sealing frame 31 is formed around the solar cell element 11 while leaving the portion of the opening 31s (see FIG. 1B) (sealing frame forming step). The sealing frame 31 is formed of, for example, a white silicone resin (adhesive). Adhesion of the covering portion 30 is improved by applying the same resin as the resin sealing portion 33. Moreover, it becomes possible to prevent the temperature rise of sealing frame 31 itself by setting it as white.

  That is, in the present embodiment, the translucent covering plate 32 is disposed and the surface sealing thickness Tsr is thinner than the delimiting surface sealing thickness DTsr before the translucent covering plate arranging step (step S13). A sealing frame forming step for forming the sealing frame 31 to be determined on the receiver substrate 20 so as to correspond to the end of the resin sealing portion 33.

  Therefore, it is possible to determine the surface sealing thickness Tsr with a sealing frame 31 on which the translucent covering plate 32 is arranged with a high accuracy with a thickness smaller than the demarcated surface sealing thickness DTsr. It is possible to easily and accurately manufacture the solar cell 10 that suppresses the above.

  As described in the second embodiment, the defined surface sealing thickness DTsr for the solar cell 10 is defined based on the foaming characteristic curve CC representing the foaming time Tvg with respect to the surface sealing thickness Tsr. Therefore, it is possible to easily and accurately define the defined surface sealing thickness DTsr by applying the foaming characteristic curve CC representing the foaming time Tvg with respect to the surface sealing thickness Tsr. It is possible to reduce the amount of sealing resin irradiated to the sunlight Ls by thinning Tsr and reliably prevent the foaming phenomenon in the long term required as a period in which foaming does not occur. Can be improved.

  It is also possible to apply an appropriate jig instead of the sealing frame 31 to determine the surface sealing thickness Tsr in a range smaller than the defined surface sealing thickness DTsr.

Step S13:
The sealing frame 31 is covered with a light-transmitting covering plate 32 and bonded and disposed (translucent covering plate disposing step). In addition, after adhering the translucent covering plate 32 to the sealing frame 31, the sealing frame 31 is hardened by performing a heat treatment at 150 ° C. for 30 minutes, for example.

  The surface sealing thickness Tsr can be controlled by appropriately pressing when the translucent cover plate 32 is bonded to the sealing frame 31, and can be fixed by curing.

Step S14:
The space formed by the receiver substrate 20, the sealing frame 31, and the translucent covering plate 32 is filled with sealing resin from the direction of arrow RF (see FIG. 1B) through the opening 31s, and the resin sealing portion 33 is formed. Form (resin sealing portion forming step). The sealing resin filled in the resin sealing portion 33 is a transparent silicone resin. After filling the sealing resin, for example, two-stage curing is performed at 80 ° C. for 2 hours and at 150 ° C. for 25 hours to cure the resin sealing portion 33.

  As described above, in the method for manufacturing solar cell 10 according to the present embodiment, the solar cell element mounting step of mounting solar cell element 11 on receiver substrate 20 and the translucency of disposing translucent covering plate 32. A covering plate arranging step and a resin sealing portion forming step for forming the resin sealing portion 33, and in the translucent covering plate arranging step, between the surface of the solar cell element 11 and the translucent covering plate 32. The surface sealing thickness Tsr, which is the thickness of the resin sealing portion 33, is translucent so as to be thinner than the defined surface sealing thickness DTsr defined by the method for manufacturing the solar cell 10 described in the second embodiment. The covering plate 32 is disposed.

  Therefore, it is possible to easily and accurately produce the highly reliable solar cell 10 in which the foaming phenomenon in the resin sealing portion 33 due to secular change does not occur.

It is sectional drawing which shows schematic structure of the solar cell which concerns on Embodiment 1 of this invention, and a concentrating solar power generation module. It is a top view which shows the state which looked at the solar cell shown to FIG. 1A from the condensing lens side. It is a schematic diagram which shows schematic structure of the acceleration test which calculates | requires a foaming characteristic curve with the manufacturing method of the solar cell which concerns on Embodiment 2 of this invention. It is a flowchart which shows the processing flow when calculating | requiring the definite surface sealing thickness by the acceleration test shown in FIG. It is explanatory drawing which shows the foaming characteristic calculated | required by the accelerated test shown in FIG. 2, (A) is a characteristic chart which shows the measured value of the foaming time with respect to surface sealing thickness, (B) is from the measured value of (A). It is the characteristic graph which calculated | required the foaming characteristic curve. It is a flowchart which shows the processing flow in the manufacturing method of the solar cell which concerns on Embodiment 3 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Solar cell 11 Solar cell element 20 Receiver board | substrate 31 Sealing frame 31s Opening part 32 Translucent coating | coated board 33 Resin sealing part 40 Concentration type photovoltaic power generation module 42 Condensing lens CC Foaming characteristic curve DTsr Defined surface sealing thickness Height Hf Height Ls, Lsf, Lsv Sunlight PLTD Peltier element SS Solar simulator Tsr Surface sealing thickness Tvg Foaming time θc Tangent inclination angle

Claims (3)

A solar cell element that photoelectrically converts sunlight collected by the condenser lens, a receiver substrate on which the solar cell element is placed, a resin sealing portion that resin-seals the solar cell element, and the resin seal A method of manufacturing a solar cell comprising a translucent covering plate that covers a surface of the stop portion on the side of the condenser lens,
A sample preparation step of preparing a plurality of samples having different surface sealing thicknesses, which is the thickness of the resin sealing portion between the surface of the solar cell element and the translucent covering plate;
An acceleration test step for measuring a foaming time during which bubbles are generated by performing an acceleration test on the sample and obtaining a foaming characteristic curve representing a relationship of the foaming time with respect to the surface sealing thickness;
A sealing thickness defining step for defining a defined surface sealing thickness from the foaming characteristic curve as a thickness for suppressing foaming from the sealing resin at the resin sealing portion by the concentrated sunlight. A method for producing a solar cell, characterized in that A solar cell element that photoelectrically converts sunlight collected by the condenser lens, a receiver substrate on which the solar cell element is placed, a resin sealing portion that resin-seals the solar cell element, and the resin seal A method of manufacturing a solar cell comprising a translucent covering plate that covers a surface of the stop portion on the side of the condenser lens,
A solar cell element mounting step of mounting the solar cell element on the receiver substrate;
A translucent covering plate arranging step of arranging the translucent covering plate;
A resin sealing portion forming step of forming the resin sealing portion,
The said surface sealing thickness which is the thickness of the said resin sealing part between the surface of the said solar cell element and the said light-transmitting coating plate in the said translucent coating board arrangement | positioning process is set to Claim 1. The translucent covering plate is arranged so as to be thinner than the demarcated surface sealing thickness defined by the solar cell production method described above. It is a manufacturing method of the solar cell of Claim 2, Comprising:
Prior to the translucent covering plate arrangement step, the resin encapsulating portion includes a sealing frame in which the translucent covering plate is disposed and the surface sealing thickness is determined to be thinner than the defined surface sealing thickness. The manufacturing method of the solar cell characterized by including the sealing frame formation process formed in the said receiver substrate corresponding to the edge part of this.

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