Structure, solar cell module, and resin film with conducting wire

Abstract

The present disclosure provides a structure (1) comprising: a connected body (2); a conducting wire (3) disposed on one surface of the connected body (2); and a resin film (4) disposed on the surface of the connected body (2) on the conducting wire (3) side, wherein the resin film (4) has at least a resin layer (5) in direct contact with the connected body (2), and the resin layer (5) is disposed so as to surround the outer periphery of the conducting wire (3).

Description

Structures, solar cell modules, and resin films with conductive wires

[0001] The present disclosure relates to structures, solar cell modules, and resin films with conductive wires.

[0002] A method of electrically connecting a conductive wire to a connected body using a resin film has been studied.

[0003] For example, in a solar cell module, a technique of connecting solar cell elements using conductive wires called bus bars and interconnectors is known. In Patent Documents 1 and 2, as one method of connecting solar cell elements using conductive wires, a technique of embedding a part of the conductive wire in a resin film and connecting the solar cell elements with this resin film with a conductive wire has been proposed. In this technique, the resin film with a conductive wire is heat-pressed onto the solar cell element to fix the conductive wire to the solar cell element and make an electrical connection.

[0004] International Publication No. 2004 / 021455 International Publication No. 2017 / 076735

[0005] The above resin film is required to stably fix the conductive wire to the connected body and obtain a stable electrical connection. Specifically, the above resin film is required to have the property of wrapping around the outer periphery of the conductive wire, that is, the embedding property, when the resin film with a conductive wire is heat-pressed onto the connected body. When the embedding property is poor, it becomes difficult to fix the conductive wire with the resin film, and there is a risk of displacement of the conductive wire. In addition, the above resin film is required to have heat resistance to withstand a high-temperature environment. When the heat resistance of the resin film is low, after electrically connecting the conductive wire to the connected body using the resin film and exposing it to a high temperature, it becomes difficult to hold the conductive wire with the resin film, and there is a risk of displacement of the conductive wire. Displacement of the conductive wire causes connection failure. However, generally, heat resistance and embedding property are physical properties that are considered to be mutually contradictory.

[0006] The present disclosure has been made in view of the above circumstances, and the main object is to provide a structure capable of stably fixing a conductive wire to a connected body and obtaining a stable electrical connection.

[0007] One embodiment of the present disclosure provides a structure comprising a connected body, a conductor disposed on one side of the connected body, and a resin film disposed on the side of the connected body facing the conductor, wherein the resin film has at least a resin layer in direct contact with the connected body, and the resin layer is arranged to enclose the outer circumference of the conductor.

[0008] Another embodiment of the present disclosure provides a solar cell module comprising: a plurality of solar cell elements; a plurality of conductors arranged on one side of the solar cell elements; a resin film arranged on the side of the solar cell elements facing the conductors; and a sealing material for sealing the solar cell elements, the conductors, and the resin film, wherein the resin film has at least a resin layer in direct contact with the solar cell elements, and the resin layer is arranged to enclose the outer circumference of the conductors.

[0009] Another embodiment of the present disclosure provides a wired resin film having a resin film and a wire disposed on one side of the resin film, wherein the resin film has at least a resin layer in direct contact with the wire, and when a test is performed in which a substrate is placed on the wire-side side of the wired resin film and vacuum heat lamination is performed at a heating temperature of 150°C, vacuum for 5 minutes, pressure of 100 kPa, and holding time of 7 minutes, the resin layer is arranged to enclose the outer circumference of the wire.

[0010] The structure described herein has the effect of stably fixing the conductor to the connected object and obtaining a stable electrical connection.

[0011] These are schematic plan views and cross-sectional views illustrating structures in this disclosure. These are schematic cross-sectional views illustrating structures not included in this disclosure. These are schematic cross-sectional views illustrating structures in this disclosure. These are schematic cross-sectional views illustrating structures in this disclosure. These are schematic cross-sectional views illustrating structures in this disclosure. These are schematic perspective views and cross-sectional views illustrating structures in this disclosure. These are schematic cross-sectional views illustrating structures in this disclosure. These are schematic cross-sectional views illustrating solar cell modules in this disclosure. These are schematic cross-sectional views illustrating solar cell modules in this disclosure. These are schematic plan views and cross-sectional views illustrating wired resin films in this disclosure. These are schematic cross-sectional views illustrating wired resin films in this disclosure. These are schematic plan views illustrating wired resin films in this disclosure.

[0012] Embodiments of this disclosure will be described below with reference to drawings and other figures. However, this disclosure can be implemented in many different ways and should not be interpreted as being limited to the embodiments described below. In addition, in order to make the explanation clearer, the drawings may schematically represent the width, thickness, shape, etc. of each part compared to the actual form, but these are merely examples and should not limit the interpretation of this disclosure. Furthermore, in this specification and each figure, elements similar to those described above with respect to previously shown figures will be denoted by the same reference numerals, and detailed explanations may be omitted as appropriate.

[0013] In this specification, when describing a configuration in which one member is placed on top of another member, unless otherwise specified, the terms "on top" or "below" include both cases: when the other member is placed directly above or below the other member so as to be in contact with it, and when the other member is placed above or below the other member via yet another member. Similarly, in this specification, when describing a configuration in which one member is placed on the surface of another member, unless otherwise specified, the terms "on the surface" or "on the surface" include both cases: when the other member is placed directly above or below the other member so as to be in contact with it, and when the other member is placed above or below the other member via yet another member.

[0014] Furthermore, in this specification, terms such as "film," "sheet," and "substrate" are not distinguished from each other based on differences in terminology.

[0015] A. Structure The structure in this disclosure comprises a connected body, a conductor disposed on one surface of the connected body, and a resin film disposed on the surface of the connected body on the conductor side, wherein the resin film has at least a resin layer in direct contact with the connected body, and the resin layer is arranged to enclose the outer circumference of the conductor.

[0016] Figure 1(a) is a schematic plan view illustrating a structure in this disclosure, and Figure 1(b) is a cross-sectional view taken along line A-A in Figure 1(a). As shown in Figures 1(a) and 1(b), the structure 1 comprises a connected body 2, a conductor 3 disposed on one side of the connected body 2, and a resin film 4 disposed on the side of the connected body 2 facing the conductor 3. In Figure 1, the resin film 4 has only a resin layer 5 that is in direct contact with the connected body 2. The resin layer 5 is arranged to enclose the outer circumference of the conductor 3. Also in Figure 1, the connected body 2 has a conductive portion 12, and the conductive portion 12 of the connected body 2 and the conductor 3 are electrically connected.

[0017] As mentioned above, in solar cell modules, a method has been proposed for connecting solar cell elements using wires. For example, a method has been proposed in which a portion of the wire is embedded in a resin film, and this wire-embedded resin film is heat-pressed onto the solar cell element to fix the wire to the solar cell element. This resin film is also called a connecting film. As the resin film, for example, a resin film having a heat-resistant layer containing polyethylene terephthalate (PET) and an embedding layer containing polyolefin resin is used.

[0018] For example, as shown in Figure 2, when using a resin film 104 having a heat-resistant layer 104a and an embedding layer 104b, the resin film 104 is positioned so that the side with the embedding layer 104b is in contact with the conductor 3. A highly fluid resin is used for the embedding layer 104b. Therefore, when the resin film with the conductor attached is heat-pressed onto the object to be connected, the resin component of the embedding layer 104b flows away, and the heat-resistant layer 104a comes into contact with the top of the conductor 3. In this case, the top of the conductor 3 is held down only by the heat-resistant layer 104a. As a result, it becomes difficult to fix the conductor with the resin film, and there is a possibility that the conductor will be misaligned. If the conductor is misaligned, there is a risk of connection failure.

[0019] In contrast, in this disclosure, the resin layer in the resin film that is in direct contact with the object to be connected is arranged to enclose the outer circumference of the conductor, thereby enabling the conductor to be stably fixed to the object to be connected and a stable electrical connection to be obtained.

[0020] In this specification, "the resin layer is arranged to enclose the outer circumference of the conductor" means that the resin layer is arranged to cover the portion of the conductor other than the contact point with the connected object.

[0021] Furthermore, when a conductor is fixed to the object to be connected using a resin film, it is thought that connection failures due to misalignment of the conductor are more likely to occur the thinner the conductor is. Therefore, this disclosure is particularly useful when the conductor is thin.

[0022] Furthermore, if the conductor is covered with solder, when the resin film with the conductor attached is heated and pressed onto the object to be connected, the resin component of the resin film softens and flows into the gap between the conductor and the object to be connected. This causes the resin film to adhere tightly to the object to be connected, and at the same time, the solder on the surface of the conductor melts and collects at the bottom of the conductor, securing contact with the object to be connected. At this time, the flow of the resin component of the resin film and the flow of the solder on the surface of the conductor are in opposition.

[0023] In the above case, if the resin film has a heat-resistant layer and an embedding layer, the resin component of the embedding layer has high fluidity. Therefore, when the resin film with the wire attached is heat-pressed onto the object to be connected, the resin component of the embedding layer tends to flow into the gap between the wire and the object before the solder on the surface of the wire flows into the gap between the wire and the object to be connected. As a result, the contact area between the wire and the object to be connected becomes smaller, and there is a risk that the contact between the wire and the object to be connected will disappear altogether. This will hinder electrical connection.

[0024] In contrast, in this disclosure, the resin layer in the resin film that is in direct contact with the object to be connected is arranged to enclose the outer circumference of the conductor, so that excessive flow of the resin component of the resin layer is suppressed. Therefore, the contact area between the conductor and the object to be connected can be secured, and a stable electrical connection can be obtained.

[0025] The structures described in this disclosure are explained below, one by one.

[0026] 1. Resin film The resin film in this disclosure has at least a resin layer that is arranged on the wire-side surface of the connected object and is in direct contact with the connected object.

[0027] The resin film only needs to have at least a resin layer that is in direct contact with the object to be connected. The resin film may be a single layer consisting only of the above-mentioned resin layer, or it may be a multilayer including the above-mentioned resin layer.

[0028] (1) Resin layer In the resin film of this disclosure, the resin layer is a layer that is in direct contact with the object to be connected.

[0029] (a) Structure of the resin layer In this disclosure, the resin layer only needs to be arranged so as to enclose the outer circumference of the conductor.

[0030] Specifically, when the thickness of the resin layer is such that a ≥ c ≥ b, where a is the thickness of the portion directly in contact with the object to be connected, b is the thickness of the portion located at the top of the conductor, and c is the thickness of the portion located at the side of the conductor. By satisfying this relationship, the thickness of the resin layer can be used to stably fix the conductor to the object to be connected and to obtain a stable electrical connection.

[0031] On the other hand, when the resin film has a heat-resistant layer and an embedding layer, as mentioned above, a highly fluid resin is used in the embedding layer. Therefore, when the resin film with the wire attached is heat-pressed onto the object to be connected, the resin component of the embedding layer flows out, and the heat-resistant layer comes into contact with the top of the wire. In this case, as shown in Figure 2, the embedding layer 104b is the part of the resin film 104 that is in direct contact with the object to be connected 2. If the thickness of the embedding layer 104b is a10 for the part that is in direct contact with the object to be connected, b10 for the part located at the top of the wire, and c10 for the part located at the side of the wire, then c10 > a10 > b10. This does not satisfy the above-mentioned relationship of resin layer thickness. Also, b10 = 0. c10 > a10 or b10 = 0 indicates that the resin component flows out too much.

[0032] Therefore, if the thickness of each part of the resin layer satisfies a ≥ c ≥ b, it can be said that excessive flow of the resin component is suppressed.

[0033] The thickness of the resin layer can be adjusted, for example, by the material of the resin layer or by the conditions when the resin film with the conductive wires is heat-pressed onto the object to be connected.

[0034] When adjusting the material of the resin layer, for example, the above relationship for the thickness of the resin layer can be satisfied by including a first resin that imparts heat-weldability and a second resin that imparts heat resistance to the resin layer. Specifically, the above relationship for the thickness of the resin layer can be satisfied by including a resin with a low melting point and a high melt mass flow rate (MFR) and a resin with a high melting point. More specifically, the above relationship for the thickness of the resin layer can be satisfied by including polyethylene resin and polypropylene resin in the resin layer. Furthermore, the thickness of the resin layer can be adjusted by adjusting the content of each resin.

[0035] Furthermore, when adjusting the conditions for heat-pressing the wired resin film onto the object to be connected, the thickness of the resin layer can be adjusted by, for example, adjusting the temperature or time. More specifically, lowering the temperature tends to increase the thickness b of the resin layer at the top of the wire. On the other hand, increasing the temperature tends to decrease the thickness b of the resin layer at the top of the wire. Therefore, for example, even if a resin film has a thickness b of approximately 0 when heat-pressed at 150°C, the above relationship for the thickness of the resin layer can be satisfied by heat-pressing at 110°C. Also, shortening the time tends to increase the thickness b of the resin layer at the top of the wire. On the other hand, lengthening the time tends to decrease the thickness b of the resin layer at the top of the wire. Therefore, for example, even if a resin film has a thickness b of approximately 0 when heat-pressed at 150°C for t hours, the above relationship for the thickness of the resin layer can be satisfied by heat-pressing for a shorter time than 150°C for t hours.

[0036] In terms of the thickness of the resin layer, the thickness a of the portion in direct contact with the connected object is not particularly limited as long as the above-described relationship for the thickness of the resin layer is satisfied. When the structure in this disclosure is a solar cell module, the thickness a is preferably, for example, 20 μm or more, more preferably 40 μm or more, and even more preferably 60 μm or more. On the other hand, when the structure in this disclosure is a solar cell module, the thickness a is preferably, for example, 150 μm or less, more preferably 120 μm or less, and even more preferably 100 μm or less. If the thickness a is within the above range, it becomes easier to satisfy the above-described relationship for the thickness of the resin layer. Specifically, when the structure in this disclosure is a solar cell module, the thickness b is preferably 20 μm or more and 150 μm or less, more preferably 40 μm or more and 120 μm or less, and even more preferably 60 μm or more and 100 μm or less.

[0037] In terms of the thickness of the resin layer, the thickness a of the portion that is in direct contact with the object to be connected refers to the thickness at a position in the surface direction of the object to be connected where the distance from the end of the conductor is 1 mm or more. For example, as shown in Figures 3(a) to 3(d), the thickness a of the portion of the resin layer 5 that is in direct contact with the object to be connected 2 is the thickness at a position in the surface direction D1 of the object to be connected 2 where the distances d1 and d2 from the end of the conductor 3 are 1 mm or more.

[0038] Furthermore, regarding the thickness of the resin layer, the thickness b of the portion located at the top of the conductor is not particularly limited as long as the above-mentioned relationship of resin layer thickness is satisfied. b > 0. When the structure in this disclosure is a solar cell module, the thickness b may be greater than 0, but is preferably 5 μm or more, more preferably 10 μm or more, and even more preferably 20 μm or more.

[0039] In terms of the thickness of the resin layer, the thickness b of the portion located at the top of the conductor is defined according to the cross-sectional shape of the conductor.

[0040] For example, as shown in Figures 3(a) to 3(d) and Figure 4, if the cross-sectional shape of the conductor 3 is circular, elliptical, semicircular, semi-elliptical, triangular, etc., and the top of the conductor 3 is fixed at one point in the cross-sectional view, then the thickness b of the portion located at the top of the conductor is denoted by b0.

[0041] On the other hand, as shown in Figures 5(a) to 5(c), for example, if the cross-sectional shape of the conductor 3 is a square, rectangle, or an ellipse with the top and bottom cut off, and the top of the conductor 3 is not fixed at a single point in the cross-sectional view, the thickness b of the portion located at the top of the conductor is the arithmetic mean of the thicknesses b1 and b2 of the portions located at the two ends E1 and E2 at the top of the conductor 3 in the cross-sectional view, and the thickness b3 of the portion located at the center C between the two ends E1 and E2 at the top of the conductor 3. Although not shown, if the cross-sectional shape of the conductor is a trapezoid, hexagon, a square with rounded corners, a rectangle with rounded corners, a trapezoid with rounded corners, etc., and the top of the conductor is not fixed at a single point in the cross-sectional view, the thickness b of the portion located at the top of the conductor is defined in the same manner as above.

[0042] Furthermore, the thickness c of the resin layer located on the side of the conductor is not particularly limited as long as the above-mentioned relationship for the thickness of the resin layer is satisfied.

[0043] In the thickness of the resin layer, the thickness c of the portion located on the side of the conductive wire refers to the thickness on a straight line passing through the center of the conductive wire and parallel to the plane direction of the connected object. For example, as shown in FIGS. 3(a) to 3(d), the thickness c of the portion located on the side of the conductive wire 3 in the resin layer 5 is the thickness on a straight line L passing through the center of the conductive wire 3 and parallel to the plane direction D1 of the connected object 2.

[0044] The thickness of each part of the resin layer is measured from an image taken using an optical microscope of the cross-section of the structure after cutting the structure in the thickness direction. The thickness of each part of the resin layer is taken as the arithmetic mean value of the measured values at any 10 points. When a plurality of conductive wires are included in one image, a plurality of measured values may be obtained from one image. Also, when taking the thickness b of the portion located at the top of the conductive wire as the arithmetic mean value of the thicknesses of the portions located at the two ends at the top of the conductive wire and the thickness of the portion located at the center of the two ends at the top of the conductive wire, for each measurement, the arithmetic mean value of the thicknesses of the portions located at the two ends at the top of the conductive wire and the thickness of the portion located at the center of the two ends at the top of the conductive wire is obtained, and the arithmetic mean value of the obtained 10 arithmetic mean values is adopted.

[0045] Also, when measuring the thickness of each part of the resin layer, the method of cutting the structure in the thickness direction is appropriately selected according to the structure of the structure. For example, methods include cutting out the cross-section of the structure and mechanically polishing the observation surface, and generating a cross-section by ion milling. In the case of the method of generating a cross-section by ion milling, when another member is arranged on the surface of the resin layer of the structure opposite to the connected object, and the other member is a glass substrate, the glass substrate may be polished and thinned in advance and then ion milling may be performed. Also, when a part of the member constituting the structure is likely to crack when cutting the structure, the resin layer is frozen using liquid nitrogen before cutting the structure. When the structure is a solar cell module, the solar cell element may be likely to crack when cutting the solar cell module. Therefore, in this case, the resin layer may be frozen using liquid nitrogen before cutting the solar cell module

[0046] (b) Material of the resin layer The resin layer in the present disclosure is a member for fixing a conductive wire. The resin layer preferably has heat weldability and embeddability. Further, the resin layer preferably has heat resistance. Here, the "heat resistance" refers to the durability against heat in the manufacturing process of a structure such as the process of thermocompression bonding a resin film with a conductive wire to a connected body, and heat in the usage environment of the structure. Further, the resin layer preferably has such a rigidity as to press the conductive wire against the connected body for electrical connection.

[0047] The resin layer preferably contains a first resin that imparts heat weldability and a second resin that imparts heat resistance.

[0048] (i) First resin The first resin is preferably a resin that imparts heat weldability and embeddability.

[0049] The melting point of the first resin is not particularly limited as long as it can satisfy the relationship with the thickness of the resin layer described above and can exhibit desired heat weldability and embeddability. When the melting point of the first resin is low, although the heat resistance decreases, the heat weldability and embeddability tend to improve. On the other hand, when the melting point of the first resin is high, although the heat weldability and embeddability decrease, the heat resistance tends to improve. Since the resin layer preferably contains a first resin that imparts heat weldability and a second resin that imparts heat resistance as described above, the melting point of the first resin is preferably lower than the melting point of the second resin described later. Further, if the melting point of the first resin is too high, it is necessary to increase the temperature when thermocompression bonding the resin film with a conductive wire to the connected body, so there is a possibility that the manufacturing cost increases or the connected body deteriorates. On the other hand, if the melting point of the first resin is too low, the difference in melting point from the second resin becomes large, so there is a possibility that extrusion molding becomes difficult.

[0050] The melting point of the first resin is measured by differential scanning calorimetry (DSC) in accordance with JIS K7121:2012. Since the resin layer preferably contains the first resin and the second resin, it is considered that there are two or more melting peaks in the DSC curve of the resin layer. In this case, in the DSC curve, peak separation is performed, and the melting point of the first resin is taken as the lower of the two melting peaks with a large peak area.

[0051] Examples of the first resin include thermoplastic resins. Examples of thermoplastic resins include polyethylene resin, ethylene vinyl acetate copolymer, and ionomer resin. Among these, polyethylene resin is preferred because of its excellent embedding properties. The following describes polyethylene resin.

[0052] (Polyethylene Resin) Examples of polyethylene resins include high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), metallocene-based linear low-density polyethylene (M-LLDPE), and very low-density polyethylene (VLDPE). Polyethylene resins may be used individually or in combination of two or more types. Among these, low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and metallocene-based linear low-density polyethylene (M-LLDPE) are preferred due to their good flexibility.

[0053] The MFR of the polyethylene resin is not particularly limited as long as it can satisfy the above-mentioned relationship between the thickness of the resin layer and exhibit the desired heat-welding and embedding properties. When the MFR of the polyethylene resin is high, heat resistance decreases, but heat-welding and embedding properties tend to improve. On the other hand, when the MFR of the polyethylene resin is low, heat-welding and embedding properties decrease, but heat resistance tends to improve. As described above, it is preferable for the resin layer to contain a first resin that imparts heat-welding properties and a second resin that imparts heat resistance, so it is preferable for the MFR of the polyethylene resin used in the first resin to be high within the range that exhibits the desired heat-welding properties.

[0054] The MFR of polyethylene resin shall be measured by Method A as specified in JIS K7210-1:2014. The measurement conditions shall be a temperature of 190°C and a load of 2.16 kg.

[0055] The density of the polyethylene resin is not particularly limited as long as it can satisfy the above-mentioned relationship with the thickness of the resin layer and exhibit the desired heat-welding and embedding properties. When the density of the polyethylene resin decreases, flexibility improves, so although heat resistance decreases, embedding properties tend to improve. On the other hand, when the density of the polyethylene resin increases, rigidity improves, so although embedding properties decrease, heat resistance tends to improve. As described above, it is preferable for the resin layer to contain a first resin that imparts heat-welding properties and a second resin that imparts heat resistance, so the density of the polyethylene resin used in the first resin is preferably low within the range that exhibits the desired heat-welding properties. The density of the polyethylene resin is measured by Method B (pycnometer method) as specified in JIS K7112:1999.

[0056] The proportion of polyethylene resin to the total resin components in the resin layer is not particularly limited as long as it can satisfy the above-mentioned relationship to the thickness of the resin layer and exhibit the desired heat-welding and embedding properties. The proportion of polyethylene resin is preferably, for example, 50% by mass or more, and more preferably 60% by mass or more. Furthermore, the proportion of polyethylene resin is preferably, for example, 90% by mass or less, and more preferably 80% by mass or less. In other words, the proportion of polyethylene resin is preferably, for example, 50% by mass or more and 90% by mass or less, and more preferably 60% by mass or more and 80% by mass or less.

[0057] The proportion of each resin component contained in each layer of a resin film can be analyzed, for example, from the peak ratio detected by scanning calorimetry (DSC), infrared spectroscopy (IR), nuclear magnetic resonance (NMR), etc.

[0058] (ii) Second resin The second resin is preferably a resin that provides heat resistance and rigidity.

[0059] The melting point of the second resin is not particularly limited as long as it can satisfy the above-mentioned relationship with the thickness of the resin layer and exhibit the desired heat resistance. When the melting point of the second resin is high, heat resistance tends to improve, although heat weldability and embedding properties decrease. On the other hand, when the melting point of the second resin is low, heat resistance tends to improve, although heat weldability and embedding properties decrease. As described above, it is preferable for the resin layer to contain a first resin that imparts heat weldability and a second resin that imparts heat resistance, so it is preferable that the melting point of the second resin is higher than the melting point of the first resin. The upper limit of the melting point of the second resin is usually 200°C or lower. Furthermore, if the melting point of the second resin is too low, the resin film may deteriorate significantly during the manufacturing process of the structure or during use of the structure. Furthermore, if the melting point of the second resin is too high, it may increase manufacturing costs because it is necessary to raise the temperature required to melt the second resin during the manufacturing of the resin film.

[0060] The method for measuring the melting point of the second resin is the same as the method for measuring the melting point of the first resin. Since the resin layer preferably contains both the first and second resins, it is assumed that there are two or more melting peaks in the DSC curve of the resin layer. In this case, peak separation is performed on the DSC curve, and the melting point of the second resin is determined by selecting the one with the higher temperature from the two melting peaks with larger peak areas.

[0061] The second resin is preferably polypropylene resin. Polypropylene resin will be described below.

[0062] (Polypropylene Resin) Examples of polypropylene resins include homopolypropylene resin (homoPP), which is a propylene homopolymer; random polypropylene resin (randomPP), which is a random copolymer of propylene and α-olefin; and block polypropylene resin (blockPP), which is a block copolymer. Polypropylene resin may be used alone or in combination of two or more types. Among these, homopolypropylene resin is preferred. Because homopolypropylene resin has high rigidity, it is possible to easily fix the wires with a resin film.

[0063] The proportion of polypropylene resin to the total resin components of the resin layer is not particularly limited as long as it can satisfy the above-mentioned relationship to the thickness of the resin layer and exhibit the desired heat resistance and rigidity. The proportion of polypropylene resin is preferably, for example, 10% by mass or more, and more preferably 20% by mass or more. Furthermore, the proportion of polypropylene resin is preferably, for example, 50% by mass or less, and more preferably 40% by mass or less. That is, the proportion of polypropylene resin is preferably, for example, 10% by mass or more and 50% by mass or less, and more preferably 20% by mass or more and 40% by mass or less. In addition, if the resin layer contains homopolypropylene resin, if the proportion of homopolypropylene resin is too low, the desired heat resistance may not be obtained. Also, if the proportion of homopolypropylene resin is too high, the embedding and adhesion may decrease.

[0064] (iii) The additive resin layer may contain additives as needed. Examples of additives include adhesion improvers, light stabilizers, antioxidants, antiblocking agents, and lubricants.

[0065] (Adhesion-enhancing agent) The resin layer may contain an adhesion-enhancing agent. By containing an adhesion-enhancing agent in the resin layer, the adhesion to the conductor and the adhesion to the connected object can be improved. Examples of adhesion-enhancing agents include silane-modified resins and silane coupling agents.

[0066] Examples of silane-modified resins include silane-modified polyolefin resins. Silane-modified polyolefin resins are copolymers of α-olefins and ethylenically unsaturated silane compounds. The copolymer may be, for example, a random copolymer, an alternating copolymer, a block copolymer, or a graft copolymer. Among these, the copolymer is preferably a graft copolymer, and more preferably a graft copolymer in which polyolefin is the main chain and ethylenically unsaturated silane compounds are polymerized as side chains. Such graft copolymers have a higher degree of freedom for the silanol groups that contribute to adhesion, and thus can further improve adhesion to the conductor and to the connected object.

[0067] Examples of α-olefins constituting the silane-modified polyolefin resin include ethylene, propylene, 1-butene, isobutylene, 1-pentene, 2-methyl-1-butene, 3-methyl-1-butene, 1-hexene, 1-heptene, 1-octene, 1-nonene, and 1-decene. The α-olefin may be used alone or in combination of two or more. Among these, polyethylene is preferred. That is, the silane-modified polyolefin resin is preferably a silane-modified polyethylene resin. As described above, it is preferable that the resin layer contains polyethylene resin. In this case, the silane-modified polyethylene resin has good compatibility with the polyethylene resin contained in the resin layer.

[0068] Furthermore, the silane-modified polyethylene resin is preferably a resin in which linear low-density polyethylene (LLDPE) is used as the main chain and ethylenically unsaturated silane compounds are used as side chains through graft polymerization.

[0069] Examples of the ethylenically unsaturated silane compounds mentioned above include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltripropoxysilane, vinyltriisopropoxysilane, vinyltributoxysilane, vinyltripentyloxysilane, vinyltriphenoxysilane, vinyltribenzyloxysilane, vinyltrimethylenedioxysilane, vinyltriethylenedioxysilane, vinylpropionyloxysilane, vinyltriacetoxysilane, and vinyltricarboxysilane. The ethylenically unsaturated silane compounds may be used individually or in combination of two or more.

[0070] Silane-modified polyolefin resin can be obtained, for example, by the manufacturing method described in Japanese Patent Publication No. 2003-46105.

[0071] Silane-modified resins may be used individually or in combination of two or more types.

[0072] The ratio of silane-modified resin to the total resin components of the resin layer is not particularly limited as long as the above-mentioned resin thickness is satisfied, and may be, for example, 25% by mass or less.

[0073] As the silane coupling agent, for example, a silane coupling agent used in the encapsulating material of solar cells can be used. The silane coupling agent may be used alone, or two or more types may be used in combination.

[0074] The content of the silane coupling agent in the resin layer is not particularly limited as long as the above relationship to the thickness of the resin layer is satisfied, and may be, for example, 5% by mass or less.

[0075] (c) Other points of the resin layer The surface of the resin layer facing the conductor may be surface-treated. That is, the resin layer may have a surface treatment on the surface facing the conductor. This can improve adhesion to the conductor and to the connected object.

[0076] The surface treatment is not particularly limited as long as it can improve adhesion to the conductor and to the connected object, and examples include corona treatment, plasma treatment, ultraviolet treatment, electron beam treatment, and flame treatment. Among these, corona treatment is preferred in terms of processing cost and reducing damage to the resin layer.

[0077] (2) Other layers When the resin film in this disclosure is a multilayer including the above-mentioned resin layer, the other layers other than the resin layer constituting the resin film are not particularly limited. Examples of other layers include a substrate layer, an adhesive layer, and a barrier film. The substrate layer and the resin layer may be arranged in this order, the substrate layer, the adhesive layer and the resin layer may be arranged in this order, and the barrier film, the adhesive layer and the resin layer may be arranged in this order.

[0078] The base layer preferably has heat resistance. Examples of the base layer include heat-resistant resin base materials. Examples of resins constituting the resin base material include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polybutylene terephthalate (PBT).

[0079] The adhesive used in the bonding layer is not particularly limited as long as it can bond the substrate layer and the resin layer, and examples include adhesives commonly used for laminating films. Furthermore, the adhesive may be, for example, a dry laminating adhesive or an extrusion laminating anchor coating agent.

[0080] The barrier film is not particularly limited as long as it has insulating properties, and can be appropriately selected from a range of general barrier films.

[0081] (3) Method for manufacturing a resin film When the resin film is a single layer consisting only of a resin layer, the method for forming the resin layer is not particularly limited. For example, a method can be used in which a resin composition for forming the resin layer is prepared and the resin composition is melt-molded. Known molding methods can be used as the melt-molding method, for example, injection molding, extrusion molding, hollow molding, compression molding, and rotational molding. The molding temperature is, for example, above the melting point of the resin composition. The upper limit of the molding temperature is adjusted as appropriate depending on the type of resin composition.

[0082] When a resin film has a base layer and a resin layer in this order, examples of methods for manufacturing the resin film include the extrusion lamination method and the co-extrusion method. When a resin film has a base layer, an adhesive layer and a resin layer in this order, examples of methods for manufacturing the resin film include the dry lamination method and the extrusion lamination method. When a resin film has a barrier film, an adhesive layer and a resin layer in this order, examples of methods for manufacturing the resin film include the dry lamination method and the extrusion lamination method.

[0083] 2. Conductors In this disclosure, the conductor is arranged on one side of the object to be connected. The conductor is typically arranged to connect to a conductive part of the object to be connected.

[0084] The cross-sectional shape of the conductor is not particularly limited and can include, for example, a circle, ellipse, semicircle, semi-ellipse, triangle, square, rectangle, trapezoid, hexagon, a square with rounded corners, a rectangle with rounded corners, a trapezoid with rounded corners, or a shape like an ellipse with the top and bottom cut off. Among these, a circular or elliptical cross-sectional shape of the conductor is preferred. When the cross-sectional shape of the conductor is circular or elliptical, the contact area between the conductor and the object to be connected is smaller compared to when the cross-sectional shape of the conductor is square or rectangular, so connection failures due to misalignment of the conductor are more likely to occur. Therefore, this disclosure is particularly useful when the cross-sectional shape of the conductor is circular or elliptical.

[0085] The thickness of the conductor, i.e., the size of the cross-section of the conductor, is not particularly limited and can be appropriately selected according to the application of the structure. When the structure in this disclosure is a solar cell module, the thickness of the conductor is not particularly limited as long as it does not obstruct the incidence of sunlight onto the solar cell elements, and may be, for example, 10 μm to 1000 μm, or 20 μm to 500 μm. As mentioned above, the thinner the conductor, the more likely connection failures are to occur due to misalignment of the conductor. Therefore, this disclosure is particularly useful when the thickness of the conductor is within the above range. The thickness of the conductor is the maximum value measured with a caliper, regardless of the cross-sectional shape of the conductor. When measuring the thickness of the conductive wire, the conductor can be removed from the structure.

[0086] The material of the conductor is not particularly limited as long as it exhibits the desired conductivity, and general conductor materials can be used. Examples of conductor materials include metallic materials such as copper (Cu), silver (Ag), gold (Au), and aluminum (Al). The conductor may also have, for example, a core portion and a skin portion disposed outside the core portion. In this case, the material of the core portion can be the metallic material mentioned above, and the material of the skin portion can be solder.

[0087] The melting point of solder is not particularly limited and is set appropriately according to the intended use and manufacturing conditions of the structure. For example, the melting point of solder is between 110°C and 300°C. If the structure is a solar cell module, the melting point of solder is, for example, between 110°C and 150°C.

[0088] The solder is not particularly limited and is selected as appropriate depending on the application and manufacturing conditions of the structure. For example, if the structure in this disclosure is a solar cell module, examples of solder include Sn-In-Ag-Bi, Sn-In, and Bi-Sn systems.

[0089] In this disclosure, it is sufficient for one or more wires to be arranged on a single resin film. From the viewpoint of conductivity, it is preferable for multiple wires to be arranged on a single resin film.

[0090] When multiple wires are arranged on a single resin film, the arrangement of the wires in a plan view is not particularly limited. For example, the wires may be arranged in a linear pattern or in a grid pattern.

[0091] If the structure in this disclosure has multiple resin films, the same conductor may be arranged on multiple resin films. For example, when the structure in this disclosure is a solar cell module, Figures 6(a) and 6(b) show an example in which the same conductor 3 is arranged on two resin films 4A and 4B. Figure 6(a) is a schematic perspective view illustrating the structure in this disclosure, and Figure 6(b) is a cross-sectional view taken along line B-B in Figure 6(a).

[0092] 3. The connected object in this disclosure is not particularly limited as long as it is electrically connected to the conductor, and can be appropriately selected according to the application of the structure. The connected object usually has a conductive part that is electrically connected to the conductor.

[0093] For example, if the structure in this disclosure is a solar cell module, the connected object is a solar cell element. In this case, the conductive part of the connected object is the electrode of the solar cell element.

[0094] 4. Joint The structure in this disclosure may or may not have a joint between the connected object and the conductor.

[0095] The material of the joint is not particularly limited as long as it is a material that can join the wire to the object to be connected, for example, solder and conductive adhesive. The solder is not particularly limited and is appropriately selected according to the application of the structure and the manufacturing conditions of the structure. The solder is the same as the solder used on the surface of the wire. The conductive adhesive is not particularly limited and is appropriately selected according to the application of the structure and the manufacturing conditions of the structure. Figure 7(a) is an example in which a joint 6a including solder is placed between the object to be connected 2 and the wire 3. Figure 7(b) is an example in which a joint 6b including conductive adhesive is placed between the object to be connected 2 and the wire 3.

[0096] If the joint includes solder, the joint including solder may be placed on one side of the objects to be connected, and then a conductor may be placed on the other side of the objects to be connected so as to be electrically connected to the joint. Alternatively, as described above, a conductor covered with solder may be used so that the joint including solder is formed by heating.

[0097] 5. Structures Examples of structures in this disclosure include solar cell modules and PC connectors.

[0098] B. Solar Cell Module The solar cell module in this disclosure comprises a plurality of solar cell elements, a plurality of conductors arranged on one side of the solar cell elements, a resin film arranged on the side of the solar cell elements facing the conductors, and a sealing material for sealing the solar cell elements, the conductors, and the resin film, wherein the resin film has at least a resin layer that is in direct contact with the solar cell elements, and the resin layer is arranged to enclose the outer circumference of the conductors.

[0099] Figures 8 and 9 are schematic cross-sectional views illustrating a solar cell module in this disclosure. As shown in Figures 8 and 9, the solar cell module 30 includes a plurality of solar cell elements 31, a plurality of conductors 3 arranged on one side of the solar cell elements 31, a resin film 4 arranged on the side of the solar cell elements 31 facing the conductors 3, and a sealing material 32 that seals the solar cell elements 31, the conductors 3, and the resin film 4. In Figures 8 and 9, the solar cell module 30 further includes a transparent substrate 33 and a back substrate 34 on both sides of the sealing material 32, respectively. In Figure 9, the resin film 4 has only a resin layer 5 that is in direct contact with the solar cell elements 31. The resin layer 5 is arranged to enclose the outer circumference of the conductors 3.

[0100] The solar cell module in this disclosure provides the same effects as the structure described above.

[0101] The following describes the solar cell modules in this disclosure, broken down by their configuration.

[0102] 1. Resin Film The resin film in this disclosure has at least a resin layer that is in direct contact with the solar cell element, and the resin layer is arranged to enclose the outer circumference of the conductor. The resin film is the same as the resin film in the structure described above.

[0103] When the thickness of the resin layer is such that a11 ≥ c11 ≥ b11, the thickness of the portion directly in contact with the solar cell element is a11, the thickness of the portion located at the top of the conductor is b11, and the thickness of the portion located at the side of the conductor is c11, it is preferable that a11 ≥ c11 ≥ b11. The thickness a11 of the portion directly in contact with the solar cell element, the thickness b11 of the portion located at the top of the conductor, and the thickness c11 of the portion located at the side of the conductor are the same as the thickness a of the portion directly in contact with the connected object, the thickness b of the portion located at the top of the conductor, and the thickness c of the portion located at the side of the conductor in the above-described structure.

[0104] 2. Conductors In this disclosure, the conductors are arranged between one side of the solar cell element and the resin layer side of the resin film. The conductors are used to connect solar cell elements to each other in a solar cell module. The conductors are used to collect electricity generated by the solar cell elements. The conductors are usually arranged to connect to the electrodes of the solar cell elements. The conductors are similar to the conductors in the structures described above.

[0105] 3. Solar Cell Elements General-purpose solar cell elements can be used as solar cell elements. Examples of solar cell elements include monocrystalline silicon solar cell elements, polycrystalline silicon solar cell elements, amorphous silicon solar cell elements, compound semiconductor solar cell elements, dye-sensitized solar cell elements, quantum dot solar cell elements, and organic thin-film solar cell elements. The size and shape of the solar cell elements can be appropriately selected according to the application of the solar cell module.

[0106] Multiple solar cell elements may be connected in series or in parallel by a wire.

[0107] 4. Encapsulating material: The encapsulating material is a component that encapsulates the solar cell elements, wires, and resin film.

[0108] The encapsulant contains a thermoplastic resin. The thermoplastic resin used in the encapsulant is the same as the thermoplastic resin used in general solar cell encapsulants. Encapsulators mainly composed of various olefin resins such as polyethylene resin and ethylene-vinyl acetate copolymer (EVA) can be used. "Mainly composed of these resins" means that these resins make up the largest proportion of all resin components.

[0109] The thickness of the encapsulant is selected appropriately depending on the type and size of the solar cell module.

[0110] 5. Joints In the solar cell module of this disclosure, joints may be provided between the solar cell elements and the conductors. The joints are the same as those in the structures described above.

[0111] 6. Transparent substrate and back substrate The transparent substrate and back substrate are components that protect the solar cell element.

[0112] The transparent substrate is typically placed on the light-receiving side of the solar cell and functions as a front protective plate on the light-receiving side. The transparency of the transparent substrate is not particularly limited, as long as it does not hinder the power generation of the solar cell elements. The transparent substrate is similar to those used in general solar cells.

[0113] The back substrate may or may not be transparent. If the back substrate is transparent, both sides of the solar cell can be used as light-receiving surfaces. The transparent substrate described above can be used as the back substrate. Alternatively, a back protective sheet for solar cells can be used as the back substrate.

[0114] 7. Method for Manufacturing Solar Cell Modules The method for manufacturing solar cell modules in this disclosure is not particularly limited as long as a structure can be obtained in which conductive wires are electrically connected to and fixed to the electrodes of the solar cell elements. For example, a manufacturing method can be cited which includes the steps of: embedding a part of the conductive wires in a resin film; temporarily bonding the resin film with the conductive wires to the solar cell elements; and laminating the various components of the solar cell module, including the solar cell elements to which the resin film with the conductive wires has been temporarily bonded, and then heat-pressing them together. Known methods can be used for the embedding method, temporary bonding method, and heat-pressing method. For example, a vacuum thermal lamination method can be cited as a heat-pressing method. In the heat-pressing step, the various components of the solar cell module are integrated together.

[0115] The conditions for the vacuum thermal lamination method can be appropriately selected according to the size of the solar cell module, the type of each component, etc., and are not particularly limited. The heating temperature is, for example, 130°C to 170°C. The holding time is, for example, 3 minutes to 30 minutes.

[0116] C. Resin film with wires The resin film with wires in this disclosure comprises a resin film and a wire disposed on one side of the resin film, wherein the resin film has at least a resin layer in direct contact with the wire, and when a test is performed in which a substrate is placed on the wire-side surface of the resin film with wires and vacuum heat lamination is performed at a heating temperature of 150°C, vacuum for 5 minutes, pressure of 100 kPa, and holding time of 7 minutes, the resin layer is arranged to enclose the outer circumference of the wire.

[0117] Figure 10(a) is a schematic plan view illustrating a wired resin film in this disclosure, and Figure 10(b) is a cross-sectional view taken along line A-A in Figure 10(a). As shown in Figures 10(a) and (b), the wired resin film 40 has a resin film 4 and a wire 3 arranged on one side of the resin film 4. In Figure 10(b), the resin film 4 has only a resin layer 5 that is in direct contact with the wire 3. Furthermore, as shown in Figure 11, when a test is performed in which a substrate 41 is placed on the wired resin film 40 on the wire 3 side and vacuum heat lamination is performed under predetermined conditions, the resin layer 5 is arranged to enclose the outer circumference of the wire 3.

[0118] The conductive resin film in this disclosure provides the same effects as the structure described above.

[0119] The conductive resin film described herein will be explained below for each component.

[0120] 1. Resin Film The resin film in this disclosure has at least a resin layer that is in direct contact with the conductor. Furthermore, when a predetermined vacuum heat lamination test is performed, the resin layer is arranged to enclose the outer circumference of the conductor.

[0121] When a predetermined vacuum thermal lamination test is performed, it is preferable that a21 ≥ c21 ≥ b21, where a21 is the thickness of the resin layer in direct contact with the substrate, b21 is the thickness of the portion located at the top of the conductor, and c21 is the thickness of the portion located at the side of the conductor. The thicknesses a21 of the portion in direct contact with the substrate, b21 of the portion located at the top of the conductor, and c21 of the portion located at the side of the conductor are the same as the thickness a of the portion in direct contact with the object to be connected, b of the portion located at the top of the conductor, and c of the portion located at the side of the conductor in the above-described structure.

[0122] The vacuum thermal lamination test is performed under the following conditions: heating temperature of 150°C, vacuum evacuation for 5 minutes, pressure of 100 kPa, and holding time of 7 minutes. A glass substrate is used as the substrate.

[0123] The resin film is the same as the resin film in the structure described above.

[0124] 2. Conductors The conductors in this disclosure are arranged on one side of the resin film. The conductors are the same as the conductors in the structure described above.

[0125] In the wired resin film of this disclosure, it is preferable that, as shown in Figure 10(b), for example, a portion of the wire 3 is embedded in the resin layer 5 of the resin film 4, and a portion of the wire 3 is exposed. This allows the wire to be securely fixed. Furthermore, if the resin film is a multilayer including a resin layer, it is preferable that the wire is embedded in the resin layer so as not to come into contact with any layers other than the resin layer. The degree to which the wire is embedded, that is, the degree to which the wire is exposed, is not particularly limited as long as it satisfies the relationship between the thickness of the resin layer when a predetermined vacuum thermal lamination test is performed, and can be appropriately selected depending on the material of the resin layer, the thickness of the resin layer, the thickness of the wire, and the application of the wired resin film.

[0126] 3. Resin Film with Conductors The method for manufacturing a resin film with conductive wires in this disclosure is not particularly limited as long as the conductive wires can be embedded to a degree that they can be fixed to the resin layer side of the resin film, and known methods can be used. For example, a method can be given in which conductive wires are placed on the resin layer side of the resin film and heated to melt a portion of the resin component in the resin layer and embed the conductive wires.

[0127] In the case of a wired resin film in this disclosure having multiple resin films, the same wire may be arranged on multiple resin films. For example, when the wired resin film in this disclosure is used in a solar cell module, Figure 12 shows an example in which the same wire 3 is arranged on two resin films 4A and 4B. Also, as shown in Figure 12, adjacent resin films may be arranged so that the surfaces facing the resin layer are in opposite directions. By having the above structure, the wired resin film can be made capable of arranging two solar cell elements in series. Although not shown, adjacent resin films may be arranged so that the surfaces facing the resin layer are in the same direction.

[0128] This disclosure is not limited to the embodiments described above. The embodiments described above are illustrative, and any configuration that is substantially identical to the technical idea described in the claims of this disclosure and achieves similar effects is included within the technical scope of this disclosure.

[0129] [Example 1] (1) Preparation of resin film Linear low-density polyethylene (LLDPE) ("Kernel KF260T" manufactured by Nippon Polyethylene Co., Ltd., density 0.9 g / cm³) ３ 60 parts by mass of a substance with a melting point of 93°C, MFR (190°C, Method A) 2.0 g / 10 min, and homopolypropylene (Prime Polymer Co., Ltd. "S135", density 0.9 g / cm³) ３A resin composition was prepared by mixing 40 parts by mass of a substance with a melting point of 165°C and MFR (230°C, Method A) 4.0 g / 10 min. A resin film consisting only of a resin layer with a thickness of 80 μm was obtained by extrusion molding of the above resin composition. Next, one side of the above resin film was subjected to corona treatment.

[0130] (2) Fabrication of the pseudo-solar cell A metal wire with a circular cross-section, a diameter of 250 μm, and coated with solder was used as the conductor. A transparent backsheet with a thickness of 155 μm (Dai Nippon Printing Co., Ltd. "TH-CP-M") was used as the transparent substrate, and a encapsulant sheet containing polyolefin resin with a thickness of 450 μm (Dai Nippon Printing Co., Ltd. "CVF") was used as the encapsulant, and an aluminum plate with a thickness of 180 μm was used as the pseudo-solar cell element, and a black backsheet with a thickness of 185 μm (Dai Nippon Printing Co., Ltd. "BE180-bR") ​​was used as the back substrate.

[0131] First, an ETFE (tetrafluoroethylene-ethylene copolymer) film was placed on the side of the resin film opposite to the resin layer. Then, nine wires and the ETFE film were arranged sequentially on the side of the resin film facing the resin layer, spaced 15 mm apart. After that, lamination was performed using a vacuum laminator at a temperature of 150°C and a pressure of 20 kPa to obtain a resin film with wires attached.

[0132] Next, a transparent substrate, a sealing material, a resin film with wires, a pseudo-solar cell element, another resin film with wires, a sealing material, and a back substrate were laminated together, and vacuum lamination was performed under the conditions of a heating temperature of 150°C, vacuum evacuation for 5 minutes, a pressure of 100 kPa, and a holding time of 7 minutes. When laminating each component, the resin film with wires was positioned so that the side with the wires faced the solar cell element.

[0133] [Comparative Example 1] A pseudo-solar cell was fabricated in the same manner as in Example 1, except that the resin film was prepared as shown below.

[0134] A low-density polyethylene (LDPE) (Sumitomo Chemical's "Sumikasen CE4009") was extruded and laminated onto one side of a polyethylene terephthalate (PET) film (DuPont's "LBD", 12 μm thick) to form an 80 μm thick resin layer, thereby obtaining a multilayer resin film. Next, the resin layer side of the resin film was subjected to corona treatment.

[0135] [Comparative Example 2] A pseudo-solar cell was fabricated in the same manner as in Example 1, except that the resin film was prepared as shown below.

[0136] Linear low-density polyethylene (LLDPE) (Kernel KF260T, manufactured by Nippon Polyethylene Co., Ltd., density 0.9 g / cm³) ３ 90 parts by mass of a substance with a melting point of 93°C, MFR (190°C, Method A) 2.0 g / 10 min, and homopolypropylene (Prime Polymer Co., Ltd. "S135", density 0.9 g / cm³) ３ A resin composition was prepared by mixing 10 parts by mass of a substance with a melting point of 165°C and MFR (230°C, Method A) 4.0 g / 10 min. A resin film consisting only of a resin layer with a thickness of 80 μm was obtained by extrusion molding of the above resin composition. Next, one side of the above resin film was subjected to corona treatment.

[0137] [Evaluation] (1) Thickness of the resin layer First, a razor blade was placed perpendicular to the wires of the pseudo-solar cell and struck with a hammer to cut through it, thus cutting the pseudo-solar cell in the thickness direction. Next, the cross-section of the pseudo-solar cell was observed using an optical microscope, and the thickness of each part of the resin layer was measured using an analysis system. The thickness of each part of the resin layer was the arithmetic mean of the 10 measured values ​​as described above.

[0138] (2) Temperature cycling test A temperature cycling test (-40°C ⇔ 90°C, 400 cycles, 1 cycle = 6 hours) was performed on the simulated solar cell. The FF (curve factor) and Pmax (maximum output) were measured before and after the temperature cycling test, and the maintenance rate was determined.

[0139]

[0140] FF is affected by the internal resistance and diode losses of the pseudo-solar cell. The larger the FF, the higher the Pmax. In other words, a decrease in FF during temperature cycling tests indicates an increase in internal resistance. One possible cause of this is poor wiring connections. As shown in Table 1, in Example 1, the FF maintenance rate and Pmax maintenance rate were higher compared to Comparative Examples 1 and 2. This confirms that poor wiring connections were suppressed.

[0141] This disclosure provides the following inventions: [1] A structure comprising: a connected body; a conductor disposed on one surface of the connected body; and a resin film disposed on the surface of the connected body on the conductor side, wherein the resin film has at least a resin layer in direct contact with the connected body, and the resin layer is disposed to enclose the outer circumference of the conductor. [2] The structure according to [1], wherein, of the thickness of the resin layer, a is the thickness of the portion in direct contact with the connected body, b is the thickness of the portion located at the top of the conductor, and c is the thickness of the portion located at the side of the conductor, a ≥ c ≥ b. [3] The structure according to [1] or [2], wherein the connected body has a conductive portion electrically connected to the conductor. [4] The structure according to any one of [1] to [3], wherein a joint portion including solder is located between the connected body and the conductor. [5] The structure according to any one of [1] to [3], wherein a joint portion including conductive adhesive is located between the connected body and the conductor. [6] The structure according to any one of [1] to [5], wherein the thickness of the conductor is 10 μm or more and 1000 μm or less. [7] A solar cell module comprising: a plurality of solar cell elements; a plurality of conductors arranged on one side of the solar cell elements; a resin film arranged on the side of the solar cell elements that is on the conductor side; and a sealing material that seals the solar cell elements, the conductors, and the resin film, wherein the resin film has at least a resin layer that is in direct contact with the solar cell elements, and the resin layer is arranged to enclose the outer circumference of the conductors. [8] The solar cell module according to [7], wherein, of the thickness of the resin layer, a11 is the thickness of the portion in direct contact with the solar cell elements, b11 is the thickness of the portion located at the top of the conductors, and c11 is the thickness of the portion located at the side of the conductors, a11 ≥ c11 ≥ b11. [9] The solar cell module according to [7] or [8], wherein a joint including solder is provided between the solar cell elements and the conductors.

[10] The solar cell module according to [7] or [8], having a joint containing a conductive adhesive between the solar cell element and the conductor.

[11] A solar cell module according to any one of [7] to

[10] , wherein the thickness of the conductor is 10 μm or more and 1000 μm or less.

[12] A resin film with a conductor, comprising a resin film and a conductor disposed on one side of the resin film, wherein the resin film has at least a resin layer in direct contact with the conductor, and when a test is performed in which a substrate is placed on the conductor-side surface of the resin film with a conductor and vacuum heat lamination is performed at a heating temperature of 150°C, vacuum for 5 minutes, pressure of 100 kPa, and holding time of 7 minutes, the resin layer is arranged to enclose the outer circumference of the conductor.

[13] A resin film with a conductor according to

[12] , wherein when the above test is performed, if the thickness of the resin layer is a21 for the part in direct contact with the substrate, b21 for the part located at the top of the conductor, and c21 for the part located on the side of the conductor, then a21 ≥ c21 ≥ b21.

[0142] 1... Structure 2... Connected object 3... Conductor wire 4, 4A, 4B... Resin film 5... Resin layer 6a, 6b... Joint 12... Conductive part 30... Solar cell module 31... Solar cell element 32... Encapsulation material 33... Transparent substrate 34... Back substrate 40... Resin film with conductor wire 41... Substrate

Claims

1. A structure comprising: a connected body; a conductor disposed on one surface of the connected body; and a resin film disposed on the surface of the connected body on the conductor side, wherein the resin film has at least a resin layer in direct contact with the connected body, and the resin layer is arranged to enclose the outer circumference of the conductor.

2. The structure according to claim 1, wherein, of the thickness of the resin layer, the thickness of the portion in direct contact with the connected object is a, the thickness of the portion located at the top of the conductor is b, and the thickness of the portion located at the side of the conductor is c, such that a ≥ c ≥ b.

3. The structure according to claim 1 or 2, wherein the connected object has a conductive portion that is electrically connected to the conductor.

4. The structure according to claim 1 or claim 2, having a joint including solder between the connected object and the conductor.

5. The structure according to claim 1 or claim 2, wherein the structure has a joint containing a conductive adhesive between the connected object and the conductor.

6. The structure according to claim 1 or claim 2, wherein the thickness of the conductor is 10 μm or more and 1000 μm or less.

7. A solar cell module comprising: a plurality of solar cell elements; a plurality of conductors arranged on one side of the solar cell elements; a resin film arranged on the side of the solar cell elements facing the conductors; and a sealing material for sealing the solar cell elements, the conductors, and the resin film, wherein the resin film has at least a resin layer that is in direct contact with the solar cell elements, and the resin layer is arranged to enclose the outer circumference of the conductors.

8. The solar cell module according to claim 7, wherein, of the thickness of the resin layer, the thickness of the portion directly in contact with the solar cell element is a, the thickness of the portion located at the top of the conductor is b, and the thickness of the portion located at the side of the conductor is c, such that a ≥ c ≥ b.

9. The solar cell module according to claim 7 or claim 8, further comprising a joint including solder between the solar cell element and the conductor.

10. The solar cell module according to claim 7 or claim 8, further comprising a joint containing a conductive adhesive between the solar cell element and the conductor.

11. The solar cell module according to claim 7 or claim 8, wherein the thickness of the conductor is 10 μm or more and 1000 μm or less.

12. A wired resin film comprising a resin film and a wire disposed on one side of the resin film, wherein the resin film has at least a resin layer in direct contact with the wire, and when a test is performed in which a substrate is placed on the wire-side surface of the wired resin film and vacuum heat lamination is performed at a heating temperature of 150°C, vacuum for 5 minutes, pressure of 100 kPa, and holding time of 7 minutes, the resin layer is arranged to enclose the outer circumference of the wire.

13. When the above test is performed, if the thickness of the resin layer is such that a21 is the thickness of the portion in direct contact with the substrate, b21 is the thickness of the portion located at the top of the conductor, and c21 is the thickness of the portion located at the side of the conductor, then a21 ≥ c21 ≥ b21, as described in claim 12.

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