Solar cell and solar panel including the same

Abstract

To provide a solar cell capable of enhancing the output power and reliability of a solar cell panel, and a solar cell panel including the same.SOLUTION: A solar cell includes a semiconductor substrate, a conductive region disposed in or on the semiconductor substrate, and an electrode including a plurality of finger lines connected to the conductive region, and formed to extend in a first direction while being parallel, and 6 or more bus bar lines formed to extend in a second direction crossing the first direction. Each bus bar line has a width of 35 to 350 μm at at least a portion thereof. Each bus bar line has a distance between one and the other ends thereof in the second direction smaller than a distance between an outermost finger line at one side and an outermost finger line at the other side in the second direction.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to a solar cell and a solar panel including the solar cell, which are connected by wiring material. The present invention relates to a solar cell and a solar panel including the same. [Background technology]

[0002] Recently, it has been predicted that existing energy resources such as oil and coal will be depleted, and alternatives to these have been developed. There is growing interest in alternative energy sources such as solar cells. It is attracting attention as a next-generation battery that converts carbon dioxide into electrical energy.

[0003] Such solar cells are connected in series or in parallel by ribbons, and Solar panel packaging process to protect the battery Solar panels must generate electricity for long periods in a variety of environments. Therefore, long-term reliability is highly required. will be connected with a ribbon.

[0004] However, when ribbons with a large width of about 1.5 mm are used to connect solar cells, In this case, the large width of the ribbon may cause optical loss, so it is necessary to The number of ribbons used must be reduced, and the ribbons must have good adhesion strength. This can cause the ribbon to bend too much, which can lead to a loss of power. However, there is a limit to how much power can be improved from solar panels, and ribbons can peel off or solar cells can be damaged. This can cause damage to the solar panel, reducing its reliability. Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention relates to a solar cell that can improve the output and reliability of a solar cell panel, and We will provide a solar panel that includes it. [Means for solving the problem]

[0006] The solar cell according to the embodiment of the present invention includes a semiconductor substrate and a semiconductor substrate. a conductive region located on the plate, and a pair of electrodes connected to the conductive region and formed in a first direction, A plurality of parallel finger lines are formed in a second direction intersecting the first direction, At least a portion of each has a width of 35 μm to 350 μm, and six or more bus bar lines are provided. The distance between one end and the other end of the bus bar line in the second direction is , a finger located at the outermost edge of one side of the plurality of finger lines in the second direction The distance is shorter than the distance between the line and the outermost finger line on the other side.

[0007] The solar cell panel according to the embodiment of the present invention includes a photoelectric conversion unit and a photovoltaic cell connected to the photoelectric conversion unit. a plurality of solar cells each including a first electrode and a second electrode; and one of the plurality of solar cells. A plurality of solar cells are connected to each other, the first electrode of one solar cell being connected to the second electrode of the adjacent solar cell. The electrode includes a plurality of parallel finger lines formed in a first direction. and six or more bus bar lines formed in a second direction intersecting the first direction. The plurality of wiring members have a diameter or width of 250 μm to 500 μm, and the bus bar Six or more of the electrodes are connected to the input terminals and arranged on one side of the solar cell. The distance between one end and the other end of the subaru line is The finger line located on the outermost edge of one side of the line and the finger line located on the outermost edge of the other side - The distance between the [Effects of the Invention]

[0008] According to this embodiment, the wiring material in the form of a wire is used to minimize the optical loss due to diffuse reflection, etc. This allows the pitch of the wiring material to be reduced, thereby reducing the number of carrier paths. This can improve the efficiency of the solar cells and the output of the solar panel. At this time, the edge distance of the first electrode is limited depending on the width of the wiring material, and the wire shape can be effectively controlled. This can improve the adhesion between the wiring material and the first electrode. 1. Prevents damage to the solar cell that may occur when it is separated from the electrode, and ensures that the solar cell It has excellent electrical properties and excellent reliability. By limiting the number of wiring materials, the output of the solar panel can be maximized. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a perspective view showing a solar cell panel according to an embodiment of the present invention; [Figure 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Figure 3] 2 is a partial cross-sectional view showing an example of a solar cell included in the solar cell panel of FIG. 1. FIG. [Figure 4] 1. FIG. 4 is a partial cross-sectional view showing another example of a solar cell included in the solar cell panel of FIG. [Figure 5] 2 is a perspective view schematically showing a first solar cell and a second solar cell connected by a wiring member in the solar cell panel of FIG. 1. FIG. [Figure 6]2A and 2B are a perspective view and a cross-sectional view showing a wiring material before being attached to an electrode of the solar cell shown in FIG. 1. [Figure 7] 2 is a cross-sectional view showing a wiring material attached to a pad portion of an electrode of the solar cell shown in FIG. 1. FIG. [Figure 8] FIG. 8 is a schematic cross-sectional view taken along line VIII-VIII in FIG. 5. [Figure 9] 2 is a plan view showing a solar cell included in the solar cell panel of FIG. 1 and wiring materials connected thereto. [Figure 10] 2 is a plan view showing a solar cell included in the solar cell panel of FIG. 1. FIG. [Figure 11] 1 is a photograph showing a cross section of a solar cell to which wiring materials having different widths are attached. [Figure 12] 10 is a graph showing the results of measuring the adhesion of a wiring material at an end of an electrode while changing the width and edge distance of the wiring material; [Figure 13] FIG. 10 is a diagram showing the output of a solar cell panel measured while varying the width and number of wiring members. [Figure 14] FIG. 10 is a partial front plan view of a solar cell according to another embodiment of the present invention. [Figure 15] FIG. 10 is a partial front plan view of a solar cell according to yet another embodiment of the present invention. [Figure 16] 10 is a graph showing the results of measuring adhesive strength by pulling a wiring material attached to a solar cell using an experimental device. DETAILED DESCRIPTION OF THE INVENTION

[0010] In the following, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to these examples, and can be modified into various forms. That's it.

[0011] In the drawings, in order to clearly and simply explain the present invention, illustrations of parts that are not relevant to the explanation are omitted. For brevity, the same drawing reference numbers will be used throughout the specification to refer to the same or very similar parts. In the drawings, thickness, area, etc. may be enlarged or reduced for clarity. The thickness, area, etc. of the present invention are not limited to those shown in the drawings.

[0012] And throughout the specification, when one part "comprises" another part, it is especially important to note that Unless otherwise stated, other moieties may be included rather than excluded. Also, when a part such as a layer, film, region, or plate is said to be "on" another part, this means that the other This includes not only the case where a part is "directly above" a layer, but also the case where another part is located between them. When a part such as a membrane, region, or plate is "directly above" another part, the other part is located in between. This means not to place

[0013] Hereinafter, a solar cell according to an embodiment of the present invention and a solar cell including the same will be described with reference to the accompanying drawings. The panels will now be described in detail.

[0014] FIG. 1 is a perspective view showing a solar cell panel according to an embodiment of the present invention, and FIG. 2 is a perspective view showing the solar cell panel shown in FIG. FIG. 2 is a cross-sectional view taken along line II-II.

[0015] Referring to FIGS. 1 and 2, a solar cell panel 100 according to this embodiment includes a plurality of solar cells. 150 and wiring material 142 that electrically connects the solar cells 150. The solar cell panel 100 includes a plurality of solar cells 150 and wiring material 142 connecting the solar cells. A sealing material 130 for sealing, and a front substrate positioned on the front surface of the solar cell 150 on the sealing material 130 110 and a rear substrate 200 positioned on the rear surface of the solar cell 150 on the encapsulant 130. This will be explained in more detail.

[0016] First, the solar cell 150 has a photoelectric conversion unit that converts solar cells into electrical energy and a photoelectric conversion and an electrode electrically connected to the switching portion for collecting and transmitting the current. The solar cells 150 are electrically connected in series, parallel, or series-parallel by wiring material 142. Specifically, the wiring material 142 may be arranged between two adjacent solar cells 150. The two solar cells 150 are electrically connected.

[0017] The bus ribbons 145 are connected by wiring material 142 to form a single row. The ends of the wiring members 142 of the solar cells 150 (i.e., solar cell strings) are alternately connected. The ribbon 145 is arranged at the end of the solar cell string in a direction crossing the solar cell string. Such a bus ribbon 145 can connect adjacent solar cell strings. or to connect a solar cell string or multiple solar cell strings with a jack to prevent reverse current flow. The bus ribbon 145 can be connected to a communication box (not shown). The quality, shape, and connection structure may be variously modified, and the present invention is not limited thereto. stomach.

[0018] The sealing material 130 includes a first sealing material 131 located in front of the solar cell 150 and a second sealing material 132 located in front of the solar cell 150. The first seal 131 and the second seal 132 may be disposed on the rear surface of the first seal 131. The sealant 132 blocks moisture and oxygen that can adversely affect the solar cells 150, and prevents the solar cell panels from The rear substrate 200 and the second sealant 13 are bonded together chemically. 2. The solar cell 150, the first encapsulant 131, and the front substrate 110 are sequentially arranged, and then the heat and and / or a lamination process that applies pressure or the like to integrate the solar cell panel 100. It is possible.

[0019] The first sealant 131 and the second sealant 132 are made of ethylene vinyl acetate copolymer resin. EVA, polyvinyl butyral, silicon resin, ester resin, olefin resin However, the present invention is not limited to this. The first and second sealing materials 131 and 132 may be formed by lamination using various other materials. In this case, the first and second sealing materials 131, 1 The light-transmitting element 32 transmits light incident through the rear substrate 200 or the rear substrate The light reflected by 200 can reach the solar cell 150.

[0020] The front substrate 110 is located on the first encapsulant 131 and forms the front surface of the solar cell panel 100. The front substrate 110 has a strength and thickness that can protect the solar cells 150 from external impacts. The front substrate 1 may be made of a material having optical transparency that allows light such as sunlight to pass through. The substrate 10 may be made of a glass substrate or the like. In this case, the strength can be improved. In this way, the front substrate 110 may be made of a tempered glass substrate, and various other properties may be improved. Various modifications are possible, such as adding various substances that can be used to Alternatively, the front substrate 110 may be a sheet or film made of resin or the like. That is, the present invention is not limited to the material of the front substrate 110, and the front substrate 110 may be various. It may be made of a material.

[0021] The rear substrate 200 is disposed on the second encapsulant 132 and is disposed on the rear side of the solar cell 150. 50 is a protective layer, which can perform waterproof, insulating and UV blocking functions.

[0022] The rear substrate 200 must be strong enough to protect the solar cells 150 from external impacts. and can transmit or reflect light depending on the desired solar panel 100 configuration. For example, the rear substrate 200 may have a characteristic that allows light to be incident thereon. In this structure, the rear substrate 200 may have a light-transmitting material, and light may be transmitted through the rear substrate 200. In the structure in which light is reflected by the back substrate 200, the back substrate 200 is made of a non-transparent material or a reflective material. For example, the rear substrate 200 may be formed in the form of a glass substrate. It may be configured in the form of a film or a sheet. For example, the rear substrate 200 It may be TPT (Tedlar / PET / Tedlar) type or poly Polyvinylidene fluoride formed on at least one surface of ethylene terephthalate (PET) (poly vinylidene fluoride, PVDF) resin Polyvinylidene fluoride is a polymer having a (CH2CF2)n structure, Double fluorine molecular structure provides excellent mechanical properties, weather resistance, and UV resistance The present invention is not limited to the material of the rear substrate 200.

[0023] 3, an example of a solar cell included in a solar panel according to an embodiment of the present invention will be described. This will be explained in more detail.

[0024] FIG. 3 is a partial cross-sectional view showing an example of a solar cell included in the solar cell panel of FIG.

[0025] Referring to FIG. 3, the solar cell 150 according to this embodiment has a semiconductor substrate including a base region 10. a plate 160 and a conductive region 20 formed in or on the semiconductor substrate 160; The conductive regions 20 and 30 are connected to electrodes 42 and 44. The regions 20, 30 are a first conductivity type region 20 having a first conductivity type and a second conductivity type region 22 having a second conductivity type. The first conductivity type region 30 may include electrodes 42 and 44 connected to the first conductivity type region 20. It may include a first electrode 42 and a second electrode 44 connected to the second conductivity type region 30 . The solar cell 150 includes a first passivation film 22, an anti-reflection film 24, a second passivation film 25, a The insulating film 32 may further be included. This will be explained in more detail.

[0026] The semiconductor substrate 160 may be composed of a crystalline semiconductor. The semiconductor layer may be made of a single crystal or polycrystalline semiconductor (for example, single crystal or polycrystalline silicon). In particular, the semiconductor substrate 160 is a single crystal semiconductor (e.g., a single crystal semiconductor wafer, more specifically In practice, the semiconductor substrate 160 may be made of a single crystal silicon wafer. When the solar cell 150 is made of a single-crystal semiconductor (for example, single-crystal silicon), the solar cell 150 The semiconductor substrate 160 is made of a crystalline semiconductor with high thermal conductivity and low defects. This allows the solar cell 150 to have excellent electrical properties.

[0027] The front and / or back surfaces of the semiconductor substrate 160 may be textured. The unevenness may be, for example, a rough surface of the semiconductor substrate 160. 11) It may have a pyramidal shape composed of faces and having irregular sizes. By such texturing, unevenness is formed on the front surface of the semiconductor substrate 160, etc. When the surface roughness increases, the reflectance of light incident through the front surface of the semiconductor substrate 160 decreases. Therefore, the region formed by the base region 10 and the first conductivity type region 20 can be This increases the amount of light that reaches the pn junction, minimizing optical loss. However, the present invention is not limited to this, and the front and rear surfaces of the semiconductor substrate 160 may be It is also possible that no texturing is formed.

[0028] The semiconductor substrate 160 contains a second conductivity type dopant at a relatively low doping concentration. The base region 10 may include a base region 10 having two conductivity types. The first conductivity type region 20 may be located further from the front surface of the semiconductor substrate 160 or further from the rear surface. The base region 10 may be located closer to the second conductivity type region 30. It may be located closer to the front surface of the conductive substrate 160 or farther from the rear surface. The present invention is not limited to this, and the position of the base region 10 may be changed. It is.

[0029] Here, the base region 10 may be made of a crystalline semiconductor containing a second conductivity type dopant. As an example, the base region 10 is made of a single crystal or polycrystalline semiconductor containing a second conductivity type dopant. (For example, monocrystalline or polycrystalline silicon) may be used. In particular, the base region 10 The second conductive type dopant is a single crystal semiconductor (e.g., a single crystal semiconductor wafer, more specifically In practice, it may be made of a single crystal silicon wafer.

[0030] The second conductivity type may be n-type or p-type. When the base region 10 has n-type, The base region 10 is made of a group 5 element such as phosphorus (P), arsenic (As), bismuth (Bi), or arsenic. It can be made of a single crystal or polycrystalline semiconductor doped with antimony (Sb) or the like. When the base region 10 has a p-type, the base region 10 is doped with boron (B), which is a group 3 element. , aluminum (Al), gallium (Ga), indium (In), etc. It can consist of a crystalline or polycrystalline semiconductor.

[0031] However, the present invention is not limited to this. The punt may be composed of a variety of materials.

[0032] As an example, the base region 10 may be of n-type. When light is irradiated onto such a pn junction, the first conductivity type region 20 has p-type conductivity. When this occurs, electrons generated by the photoelectric effect move to the rear side of the semiconductor substrate 160 and The holes are collected by the electrode 44 and move to the front side of the semiconductor substrate 160 and are introduced into the first electrode 42. This generates electrical energy. Slow-diffusing holes move to the front surface of the semiconductor substrate 160 instead of the rear surface, improving conversion efficiency. However, the present invention is not limited to this, and the base region 10 and It is also possible that the second conductivity type region 30 has the p-type and the first conductivity type region 20 has the n-type.

[0033] The front side of the semiconductor substrate 160 is provided with a first conductive layer having a first conductivity type opposite to that of the base region 10. The first conductivity type region 20 can be formed as a pn junction with the base region 10. are formed to form an emitter region that generates carriers by photoelectric conversion.

[0034] In this embodiment, the first conductivity type region 20 is a doped silicon nitride film that forms part of the semiconductor substrate 160. This allows the first conductivity type region 20 to be configured as a first conductivity type dopant. As an example, the first conductivity type region 20 may be made of a crystalline semiconductor containing a first conductivity type dopant. It is composed of a monocrystalline or polycrystalline semiconductor (for example, monocrystalline or polycrystalline silicon) containing a gallium nitride. In particular, the first conductivity type region 20 may be formed of a single crystal semiconductor containing a first conductivity type dopant. a single crystal semiconductor wafer, more specifically, a single crystal silicon wafer. In this way, when the first conductivity type region 20 constitutes a part of the semiconductor substrate 160, The junction characteristics between the source region 10 and the first conductivity type region 20 can be improved.

[0035] However, the present invention is not limited to this, and the first conductivity type region 20 may be formed in a semiconductor substrate. The first conductivity type region 160 may be formed separately from the semiconductor substrate 160. 20 is made of a crystal different from that of the semiconductor substrate 160 so that it can be easily formed on the semiconductor substrate 160. For example, the first conductivity type region 20 can be formed by deposition or the like. Amorphous, microcrystalline, or polycrystalline semiconductors can be easily manufactured by a variety of methods. A first silicon substrate (for example, amorphous silicon, microcrystalline silicon, or polycrystalline silicon) is It can be formed by doping with a conductive dopant. Various other modifications are possible. .

[0036] The first conductivity type may be p-type or n-type. When the first conductivity type region 20 has p-type, The first conductivity type region 20 is made of boron (B), aluminum (Al), gallium (Ga), which are group 3 elements. It is made of a single crystal or polycrystalline semiconductor doped with gallium (Ga), indium (In), etc. When the first conductivity type region 20 has n-type conductivity, the first conductivity type region 20 can be Group 5 elements such as phosphorus (P), arsenic (As), bismuth (Bi), and antimony (Sb) The first conductivity type may be a doped monocrystalline or polycrystalline semiconductor. Region 20 may be a boron-doped monocrystalline or polycrystalline semiconductor. The invention is not limited thereto, and various materials may be used as the first conductivity type dopant. This may also be done.

[0037] In the figure, the first conductivity type region 20 has a uniform structure (h However, the present invention However, the present invention is not limited to this. Therefore, as another embodiment, as shown in FIG. The first conductivity type region 20 has a selective structure. It is possible.

[0038] Referring to FIG. 4, the first conductivity type region 20 having the selective structure is adjacent to the first electrode 42. The first portion 20a is formed in contact with the first portion 20a, and the other portion is formed in the other portion. and a second portion 20b formed thereon.

[0039] The first portion 20a has a high doping concentration and a relatively low resistance, and the second portion 2 The first portion 20b has a lower doping concentration than the first portion 20a and has a relatively high resistance. The thickness of the first portion 20a can be made thicker than that of the second portion 20b. That is, the junction depth of the first portion 20a is may be greater than the junction depth of the second portion 20b.

[0040] In this way, in this embodiment, the portions other than the first electrode 42 where light is incident have a relatively high resistance. By forming the second portion 20b of the resistor, a shallow emitter ) is realized. This makes it possible to improve the current density of the solar cell 150. At the same time, a first portion 20a having a relatively low resistance is formed in the portion adjacent to the first electrode 42. This reduces the contact resistance with the first electrode 42. This maximizes efficiency. It can be made into

[0041] The first conductivity type region 20 may have various other structures and shapes. This may also be done.

[0042] Referring again to FIG. 3, the rear surface of the semiconductor substrate 160 is provided with a second region identical to the base region 10. and the base region 10 has a second conductivity type dopant at a higher doping concentration than the base region 10. The second conductivity type region 30 can be formed. The second conductivity type region 30 can be formed by forming a back surface field (BF) k surface field) on the surface of the semiconductor substrate 160 (more precisely, , the rear surface of the semiconductor substrate 160) to prevent carrier loss due to recombination. This forms the back surface field region.

[0043] In this embodiment, the second conductivity type region 30 is a doped silicon nitride film that forms part of the semiconductor substrate 160. This allows the second conductivity type region 30 to be configured as a second conductivity type dopant. As an example, the second conductivity type region 30 may be made of a crystalline semiconductor containing a second conductivity type dopant. It is composed of a monocrystalline or polycrystalline semiconductor (for example, monocrystalline or polycrystalline silicon) containing a gallium nitride. In particular, the second conductivity type region 30 may be formed of a single crystal semiconductor containing a second conductivity type dopant. a single crystal semiconductor wafer, more specifically, a single crystal silicon wafer. In this way, when the second conductivity type region 30 constitutes a part of the semiconductor substrate 160, The junction characteristics between the source region 10 and the second conductivity type region 30 can be improved.

[0044] However, the present invention is not limited to this, and the second conductivity type region 30 may be formed in a semiconductor substrate. 160, the second conductive type region 3 may be formed separately from the semiconductor substrate 160. 0 has a different crystal structure from the semiconductor substrate 160 so that it can be easily formed on the semiconductor substrate 160. For example, the second conductivity type region 30 can be formed by deposition or the like. Amorphous, microcrystalline, or polycrystalline semiconductors that can be easily manufactured by various methods (for example, amorphous silicon, microcrystalline silicon, or polycrystalline silicon) It can be formed by doping with an electron type dopant. Various other modifications are possible.

[0045] The second conductivity type may be n-type or p-type. When the second conductivity type region 30 has n-type, The second conductivity type region 30 is made of group 5 elements such as phosphorus (P), arsenic (As), and bismuth (B i) It can be made of a single crystal or polycrystalline semiconductor doped with antimony (Sb) or the like. When the second conductivity type region 30 has a p-type, the second conductivity type region 30 can be formed by adding a Group 3 element. Boron (B), aluminum (Al), gallium (Ga), indium (In), etc. The second conductivity type may be a doped monocrystalline or polycrystalline semiconductor. Region 30 may be a phosphorus-doped monocrystalline or polycrystalline semiconductor. The invention is not limited to this, and various materials can be used as the second conductivity type dopant. The second conductivity type dopant in the second conductivity type region 30 may be the first conductivity type dopant in the base region 10. The material may be the same as the second conductivity type dopant, or may be a different material.

[0046] In this embodiment, the second conductivity type region 30 is a uniform region having a uniform doping concentration throughout. It was shown that the compound has a homogeneous structure. However, the present invention is not limited to this. The mold region 30 can have a selective structure. In the selective structure, the second conductive type region 30 has a high potential in a portion adjacent to the second electrode 44. doping concentration, large junction depth and low resistance, and low doping elsewhere The second conductive layer can have a high doping concentration, a small junction depth, and a high resistance. The selective structure of the first conductivity type region 30 is the same as or similar to the selective structure of the first conductivity type region 20 shown in FIG. Since the first conductivity type region 20 of the selective structure is substantially the same as that described with reference to FIG. Light can be applied to the second conductivity type region 30. In yet another embodiment, as shown in FIG. The second conductivity type region 30 may have a local structure. Cut.

[0047] Referring to FIG. 4, the second conductivity type region 30 having a local structure is connected to a second electrode 44. The first portion 30a is formed locally at the portion where the second electrode 44 is to be formed. In the connected portion, the second conductivity type region 30 is located to reduce the contact resistance with the second electrode 44. , and can maintain excellent fill factor (FF) characteristics In the portion not connected to the second electrode 44, a second conductive layer is formed by a doping region. By not forming the doped region 30, recombination that may occur in the doped region is reduced, and the short circuit current Improved density (short-circuit current, Jsc) and open circuit voltage In addition, the internal quantum efficiency (int) can be increased in the area where the second conductivity type region 30 is not formed. It has excellent internal quantum efficiency (IQE) values. Therefore, the doping region is entirely Compared with the uniform structure and selective structure formed, the characteristics for long wavelength light are significantly improved. In this way, the second conductivity type region 30 of the local structure can be Efficiency-related fill factor, short circuit current density and open circuit voltage are all maintained at excellent levels As a result, the efficiency of the solar cell 150 can be improved.

[0048] The second conductivity type region 30 may have various other structures.

[0049] Referring again to FIG. 3, on the front side of the semiconductor substrate 160, more precisely, the semiconductor substrate 16 A first passivation film 22 and an anti-reflective film 23 are formed on the first conductivity type region 20 formed on or above the first conductivity type region 20. The antireflection film 24 is then formed, and the first electrode 42 is then formed on the first passivation film 22 and the antireflection film 24. Electrical connection (e.g., through opening 102) to first conductivity type region 20 is made through film 24. More specifically, contacted.

[0050] The first passivation film 22 and the anti-reflection film 24 have an opening 1 corresponding to the first electrode 42. 1. Except for 02, the semiconductor substrate 160 may be formed over substantially the entire front surface thereof.

[0051] The first passivation film 22 is formed in contact with the first conductivity type region 20 and has the first conductivity type. This passivates defects present on the surface or in the bulk of the mold region 20. By removing carrier recombination sites, the open circuit voltage (Voc) of the solar cell 150 can be increased. The anti-reflection film 24 reduces the reflectance of light incident on the front surface of the semiconductor substrate 160. This reduces the reflectance of light incident through the front surface of the semiconductor substrate 160. As a result, the pn junction formed by the base region 10 and the first conductivity type region 20 is reached. This increases the amount of light reaching the solar cell 150. c) can be increased. The film 24 increases the open circuit voltage and short circuit current of the solar cell 150, thereby improving the efficiency of the solar cell 150. can be improved.

[0052] The first passivation film 22 can be made of various materials. The passivation film 22 may be a silicon nitride film, a hydrogen-containing silicon nitride film, a silicon oxide film, Silicon oxide nitride, aluminum oxide, MgF2, ZnS, TiO2 and CeO2 Any one single film selected from the group consisting of: As an example, the first passivation film 22 may have a first conductivity type When the region 20 has an n-type, a silicon oxide film or a silicon nitride film having a fixed positive charge is used. When the first conductivity type region 20 has a p-type, a fixed negative charge may be included. The insulating layer may include an aluminum oxide film.

[0053] The anti-radiation coating 24 can be made of various materials. silicon nitride film, hydrogen-containing silicon nitride film, silicon oxide film, silicon oxynitride film, Aluminum oxide film, MgF2, ZnS, TiO2 and CeO2 It can have a single film or a multi-layer structure that combines two or more films. As an example, the anti-reflective coating 24 can include silicon nitride.

[0054] However, the present invention is not limited to this. Of course, the anti-reflection film 24 can contain various materials. Either the reflection film 22 or the anti-reflection film 24 serves as both an anti-reflection film and a passivation film. It is also possible that the first passive Various films other than the insulation film 22 and the anti-reflection film 24 are formed on the semiconductor substrate 160. Many other variations are possible.

[0055] The first electrode 42 is formed through an opening formed in the first passivation film 22 and the anti-reflection film 24. 102 (i.e., through the first passivation film 22 and the anti-reflection film 24). The first electrode 42 is electrically connected to the first conductivity type region 20. Such a first electrode 42 has excellent electrical conductivity. The first electrode 42 may be made of a material such as a metal, for example. The specific shape will be described later with reference to FIGS. 9 and 10. I will explain again in.

[0056] A second conductive layer formed on the rear surface of the semiconductor substrate 160, more precisely, in the semiconductor substrate 160. A second passivation film 32 is formed on the mold region 30, and a second electrode 44 is formed on the second passivation film 32. The second conductivity type region 30 is electrically connected to the second conductivity type region 30 through the isolation film 32 (i.e., through the opening 104). To be connected (for example, to be in contact).

[0057] The second passivation film 32 is substantially The insulating layer 164 may be formed over the entire rear surface of the semiconductor substrate 160.

[0058] The second passivation film 32 is formed in contact with the second conductivity type region 30 and has a second conductivity type. This passivates defects present on the surface or in the bulk of the mold region 30. By removing carrier recombination sites, the open circuit voltage (Voc) of the solar cell 150 can be increased. This can be done.

[0059] The second passivation film 32 can be formed of various materials. 2 The passivation film 32 is a silicon nitride film, a hydrogen-containing silicon nitride film, a silicon oxide film, or the like. film, silicon oxynitride film, aluminum oxide film, MgF2, ZnS, TiO2 and CeO2 Any one single membrane selected from the group consisting of: The second passivation film 32 may have a multi-layer structure. When the charge type region 30 has an n-type, a silicon oxide film or a silicon nitride film having a fixed positive charge is used. When the second conductivity type region 30 has a p-type, the fixed negative charge can be The film may include an aluminum oxide film having such a structure.

[0060] However, the present invention is not limited to this, and the second passivation film 32 may be formed in various ways. Alternatively, the second passivation film 32 may contain other materials. Various films may be formed on the rear surface of the semiconductor substrate 160. It is Noh.

[0061] The second electrode 44 is connected to the second passivation film 32 through an opening 104 formed in the second passivation film 32. The second electrode 44 is electrically connected to the conductive region 30. The second electrode 44 may be made of a material (for example, a metal) or the like. It may be formed with a pattern, the specific shape of which will be described again later.

[0062] In this way, in this embodiment, the first and second electrodes 42, 44 of the solar cell 150 are By having the turns, the solar cell 150 allows light to be incident on the front and rear surfaces of the semiconductor substrate 160. This allows the solar cell 150 to receive light from both sides. This can contribute to improving the efficiency of the solar cell 150 by increasing the amount of light used.

[0063] However, the present invention is not limited to this. The second electrode 44 may be formed on the semiconductor substrate 160. It is also possible to have a structure in which the entire structure is formed on the rear side. The regions 20 and 30 and the first and second electrodes 42 and 44 are disposed on one surface (e.g., The first and second conductivity type regions 20, 30 may be located together on the rear side. At least one of the layers may be formed on both sides of the semiconductor substrate 160. That is, the solar cell 150 described above is presented only as an example, and the present invention This is not limiting.

[0064] The solar cells 150 described above are electrically connected to adjacent solar cells 150 by wiring materials 142. , which will be described in more detail with reference to FIG. 5 in conjunction with FIGS. 1 and 2.

[0065] FIG. 5 shows the first solar cell connected by wiring material 142 in the solar cell panel 100 of FIG. 5 is a perspective view showing a solar cell 151 and a second solar cell 152. The battery 150 is simply shown with the semiconductor substrate 160 and the electrodes 42 and 44 at the center. 1 shows the wiring material 142 before being attached to the electrodes 42, 44 of the solar cell 150 shown in FIG. 7 is a perspective view and a cross-sectional view of the packing of the electrodes 42, 44 of the solar cell 150 shown in FIG. 10A and 10B are cross-sectional views showing the wiring material 142 attached to the lead portion (reference numeral 422 in FIG. 9 or FIG. 10). 8 is a schematic cross-sectional view taken along line VIII-VIII in FIG. For the purposes of illustration and description, only the pad portion 422 and the wiring material 142 are shown in FIG. 1, the wiring material 142 connecting the first solar cell 151 and the second solar cell 152 is mainly shown. Ta.

[0066] As shown in FIG. 5, two adjacent solar cells 150 50 (for example, a first solar cell 151 and a second solar cell 152) are connected by wiring material 142. At this time, the wiring member 142 is connected to the first electrode 144 located in front of the first solar cell 151. The electrode 42 and the second solar cell 152 located on one side of the first solar cell 151 (the lower left side of the figure) The second electrode 44 is connected to the rear surface of the first solar cell. The second electrode 44 located on the rear surface of the cell 151 and the other side of the first solar cell 151 (the right side of the figure) The first electrode 42 is connected to the front surface of another solar cell (top). Further, another wiring member 1420b is connected to the first electrode 42 located on the front surface of the second solar cell 152 and the second The solar cell 152 is located on one side (the lower left side of the figure) of the solar cell 152, and the solar cell 152 is located on the rear side of the other solar cell. The second electrode 44 is connected to the wiring material 142. , 1420a, 1420b can be connected to each other in a row. The wiring material 142 is a wiring material that connects two adjacent solar cells 150. The wire 142 can be applied to the wire 142.

[0067] In this embodiment, the wiring material 142 is connected to the first electrode 42 (more Specifically, the first electrode 42 is connected to the bus bar line 42b, and the second edge portion 16 2 to the opposite first edge 161; The second electrode 44 (more specifically, the bus bar line 44 of the second electrode 44) is connected to the rear surface of the battery 152. b) from the first edge 161 to the opposing second edge 162 The second portion 1422 extends elongately, and the second portion 1422 extends from the front surface of the second edge 162 of the first solar cell 151 to the second edge 162 of the first solar cell 151. The second portion 1421 extends to the rear surface of the solar cell 152 and connects the first portion 1421 and the second portion 1422. The wiring material 142 may include the first solar cell 15 and the second solar cell 16. After passing through the first solar cell 151 in a partial area of ​​1, The wiring material 142 may be positioned across the second solar cell 152. In this manner, the wiring material 142 may be positioned across the first and second solar cells 152. The width of the first and second solar cells 151 and 152 is smaller than that of the first and second solar cells 151 and 152. The wiring pattern is formed only in a portion corresponding to the wiring pattern (for example, the bus bar electrode 42b) and has a small area. This also allows the first and second solar cells 151, 152 to be connected effectively.

[0068] For example, the wiring material 142 may be a bus bar line 44 between the first and second electrodes 42 and 44. 2b and extends long along the bus bar line 42b while contacting the bus bar line 42b. As a result, the wiring member 142 and the first and second electrodes 42 and 44 are continuously connected. However, the present invention is not limited to this. However, the present invention is not limited to this. It is also possible to not provide the bus bar line 42b. In this case, the wiring material 142 has a plurality of fingers in a direction intersecting the finger line 42a. The electrode 42a is arranged to cross the line 42a and contact and connect to the plurality of finger electrodes 42a. However, the present invention is not limited to this.

[0069] When one surface of each solar cell 150 is taken as a reference, a plurality of wiring members 142 are provided. This can improve the electrical connection characteristics of the adjacent solar cells 150. In this case, the wiring material 142 is made of a relatively wide material (for example, 1 mm to 2 mm) that has been used previously. ) is composed of a wire having a width smaller than that of a ribbon, and one surface of each solar cell 150 Based on the number of ribbons, the number of wiring materials 142 is larger than the number of existing ribbons (for example, 2 to 5). Use.

[0070] In this embodiment, the wiring material 142 includes a core layer 142a as shown in FIG. The coating layer 142b is thinly coated on the surface of the coating layer 142a. The core layer 142a is made of a wire or the like having excellent electrical conductivity, and can conduct current. The coating layer 142b protects the core layer 142a and prevents the wiring material 14 It can play various roles such as improving the adhesion properties of 2. The coating layer 142b contains a solder material, and is melted by heat to form the wiring material 1. 42 can easily adhere to the electrodes 42 and 44. The wiring material 142 is placed on the electrodes 42 and 44 without using any adhesive or the like, and then heat is applied. Therefore, the wiring material 142 is soldered to the electrodes 42 and 44. This simplifies the tabbing process. It is possible.

[0071] At this time, the tabbing process involves applying flux to the wiring material 142, and then This can be done by placing the wiring material 142 on the electrodes 42 and 44 and then applying heat. Flux is used to prevent the formation of an oxide film that interferes with soldering, and is not necessarily used. It is not necessary to use either.

[0072] The core layer 142a is made of a material that can have excellent electrical conductivity (e.g., a metal, more specifically, Ni, Cu, Ag, Al) as the main substance (for example, substances that contain 50 wt% or more, Specifically, the coating layer 142 may contain 90 wt% or more of the substance. When b contains a solder material, the coating layer 142b contains Pb, Sn, SnIn, Sn Contains Bi, SnPb, SnPbAg, SnCuAg, SnCu, etc. as main substances However, the present invention is not limited to this, and the core layer 142a and The coating layer 142b can include a variety of materials.

[0073] Alternatively, the wiring material 142 may be attached to the electrodes 42 and 44 using a separate conductive adhesive. In this case, the wiring material 142 may include a coating layer 142b. The conductive adhesive may be an epoxy-based synthetic resin or a silicon-based synthetic resin. Ni, Al, Ag, Cu, Pb, Sn, SnIn, SnBi, SnP, SnPbAg, S Conductive particles such as nCuAg and SnCu The included material may be a material that exists in liquid form and that thermosets upon application of heat. When using such a conductive adhesive, the conductive adhesive is placed on the electrodes 42 and 44. Then, the wiring material 142 is placed on the surface of the wiring material 142, and then heat is applied to the wiring material 142. After applying or placing the conductive adhesive, place it on the electrodes 42, 44 and apply heat. This allows the wiring material 142 to be attached to the electrodes 42 and 44.

[0074] In this way, a wire having a width smaller than that of the existing ribbon is used as the wiring material 142. In this case, the material cost can be significantly reduced. Since the width is small, a sufficient number of wiring members 142 are provided to minimize the distance that carriers travel. By doing so, the output of the solar cell panel 100 can be improved.

[0075] The wires constituting the wiring material 142 according to this embodiment may be circular, elliptical, or curved. By having a cross section made of a thin film or a round cross section, reflection or diffused reflection can be induced. This allows the light reflected by the rounded surfaces of the wires that make up the wiring material 142 to , the front substrate 110 or the rear substrate 200 located on the front or rear side of the solar cell 150. The light can be reflected or totally reflected back to the solar cell 150. This effectively improves the output of the solar panel 100. Therefore, the shape of the wire constituting the wiring material 142 may be rectangular or the like. The shape of the polygon may be any of a variety of other shapes.

[0076] In this embodiment, the width W1 of the wiring material 142 may be 250 μm to 500 μm. The wire-shaped wiring material 142 having such a width can effectively The current can be efficiently transmitted to the outside or to another solar cell 150. The wiring material 142 is not inserted into a separate layer, film, etc., and is used to charge the solar cell 150. The wiring material 142 can be individually positioned and fixed on the poles 42 and 44. If the width W1 is less than 250 μm, the strength of the wiring material 142 may be insufficient, and the electrode The connection area of ​​42 and 44 is very small, so the electrical connection characteristics are poor and the adhesion is low. If the width W1 of the wiring material 142 exceeds 500 μm, the cost of the wiring material 142 increases. However, the wiring material 142 prevents light from entering the front surface of the solar cell 150, resulting in optical loss ( In addition, the electrodes 42 and 44 in the wiring material 142 may increase the shading loss. Since the force acting in the direction separating the wiring material 142 from the electrodes 42 and 44 increases, This reduces the adhesion of the electrodes 42 and 44 or the semiconductor substrate 160, causing problems such as cracks. As an example, the width W1 of the wiring material 142 may be 350 μm to 450 μm (especially In this range, the thickness of the electrodes 42 and 44 may be 350 μm to 400 μm. This can increase adhesion and improve output.

[0077] Here, before the tabbing process, the thickness T 2 is 10% or less of the width of the core layer 142a (for example, 20 μm or less, for example, 7 μm to 2 At this time, the thickness of the coating layer 142b is less than 7 μm. If the coating layer 142b is too thin, the tabbing process may not be carried out smoothly. If the thickness exceeds 20 μm, the material cost increases and the width of the core layer 142a becomes small. In this case, the strength of the wiring material 142 may be reduced. After the coating layer 142 is attached to the solar cell 150, as shown in FIG. The flow of the electricity flows down between the wiring material 142 and the solar cell 150 (more precisely, between the wiring material 142 and the electrode 4 2, 44 and the pad portion 422 of the core layer 142a) and is thicker on the other surfaces of the core layer 142a. The portion between the wiring material 142 and the solar cell 150 is thin. has a width W7 equal to or greater than the diameter of the core layer 142a of the wiring material 142. The coating is formed between the wiring material 142 and the pad portion 422 of the electrodes 42, 44. The thickness T1 of the core layer 142b may be 11 μm to 21 μm. The thickness T2 of the coating layer 142b on the surface at the portion is 2 μm or less (for example, It can have a very thin thickness of 0.5 μm to 1.5 μm. The width W1 of the wiring member 142 in the specification is the width W1 of the solar cell 150 passing through the center of the wiring member 142. It may refer to the width or diameter of the core layer 142a in a plane perpendicular to the thickness direction. The coating layer 142b has a very thin thickness at the central portion of 142a. Since the coating layer 142b does not have a significant effect on the width of the wiring material 142, The width W1 of the solar cell 150 is a plane that passes through the center of the core layer 142a and is perpendicular to the thickness direction of the solar cell 150. It may also mean the sum of the widths or diameters of the core layer 142a and the coating layer 142b.

[0078] In this way, by providing the wire-shaped wiring material 142, it is possible to achieve the effect of improving output. However, in this embodiment, the wiring material 142 having a thinner width than the conventional wiring material is used to connect adjacent wiring materials. The solar cell 150 is electrically connected to the wiring material 142, and the adhesion area between the wiring material 142 and the electrodes 42, 44 is Furthermore, if the wiring material 142 is circular or elliptical, the adhesive force may be insufficient. Alternatively, if the cross section has a curved, rounded shape, the contact area with the electrodes 42 and 44 will be larger. Therefore, the adhesion strength between the wiring material 14 and the electrodes 42 and 44 may not be strong. When the wiring material 2 has a circular, elliptical or curved round cross section, the wiring material 1 42 is thicker, the solar cell 150 or the semiconductor substrate 160 can bend more easily. There is.

[0079] In particular, between the first solar cell 151 and the second solar cell 152, the wiring material 142 is The connection must be made from the front surface of the battery 151 to the rear surface of the second solar cell 152. That is, as shown in FIG. 8, the first portion of the lead 142 may bend. Portion 1421 is attached to (for example, contact) first electrode 42 of first solar cell 151. ) state, and the second portion 1422 of the wiring member 142 is connected to the second solar cell 152. The wiring material is maintained in a state of being attached to (for example, in contact with) the electrode 44. The third part 1423 of the 142 is a part of the first part 1421 and the second part 1422. The third portion 1423 must be connected so as not to bend. The first solar cell 151 is positioned on the front side so as to have a certain distance from the first solar cell 151 near the edge of the first solar cell 151. The portion 1423a that bends to have a bulging arc shape, and the portion 1423a and the inflection point and is connected to the second solar cell 152 at a certain distance near the edge of the second solar cell 152. and a portion 1423b that is curved to have an arc shape that bulges out toward the rear side. can.

[0080] In this way, the bending portions 1423a and 1423b of the third portion 1423 are the same as those of the first portion 14 21 or the connection portion with the second portion 1422 (i.e., the edge of the first solar cell 151 or the second solar cell At the edge of the solar cell 152, the distance from the first or second solar cell 151, 152 increases. As a result, the solar cell 150 has a portion that faces in the direction of the arrow. Therefore, the lead 142 receives a force in a direction away from the electrodes 42 and 44.

[0081] The boundary between the first portion 1421 and the third portion 1423 or the boundary between the second portion 1422 and the third portion 1424 23 (i.e., the portion where the wiring material 142 and the electrodes 42 and 44 are finally connected) The closer to the edge of the pond 150, the smaller the radius of curvature of the arc. The wiring material 142 adjacent to the edge of the solar cell 150 receives a large force in the direction away from the solar cell 150. This may result in a decrease in the adhesive strength between the wiring material 142 and the electrodes 42 and 44. In the case where the wiring member 142 is provided in a wire shape, the portion where the wiring member 142 is connected is Therefore, the ends of the electrodes 42 and 44 must be spaced apart from the edges of the solar cell 150 by a certain distance or more. For example, the wiring material 142 and the electrodes 42 and 44 are bonded together with sufficient bonding or adhesive strength. I can't.

[0082] In this embodiment, the electrodes 42 and 44 of the solar cell 150 are formed in consideration of this. 9 and 10, the first electric After the detailed description of electrode 42, the second electrode 44 will be described.

[0083] FIG. 9 shows the solar cells included in the solar panel of FIG. 1 and the wiring material connected to them. 10 is a plan view showing a solar cell included in the solar cell panel of FIG. be.

[0084] 9 and 10, in this embodiment, a solar cell 150 (or a semiconductor substrate 1 60) can be divided into an electrode area EA and an edge area PA. 150 (or semiconductor substrate 160) is, for example, a first and the second edges 161, 162 and the finger line 42a intersect (for example, perpendicular or The third and fourth edges 163, 164 may be formed so as to intersect at an angle. The first and second edges 161 and 162 are substantially perpendicular to the first and second edges 163 and 164, respectively. a central portion 163a, 164a that intersects with the third or fourth edge portion 163, 164 and occupies a large portion of the third or fourth edge portion 163, 164; The first and second edge portions 161 and 162 are connected at an angle from the central portions 163a and 164a, respectively. The inclined portions 163b, 163b may be formed in a flat manner. In plan view, the solar cell 150 may have a substantially octagonal shape. The planar shape of the solar cell 150 is not limited to this, and may have various shapes.

[0085] In this embodiment, the electrode area EA is formed by finger lines 42a that are parallel to each other. The edge region PA may be a region where the fins are arranged at a uniform pitch P. The finger lines 42a are not located or the density of the finger lines 42a in the electrode area EA is In this embodiment, the edge region PA may be a region where the electrode portions are located at a lower density than the edge region PA. 2 shows an example in which the electrode portion of the first electrode 42 is not positioned.

[0086] In this embodiment, the electrode area EA is defined by the bus bar line 42b or the wiring material 142. More specifically, the electrode area EA can be The area EA is a first electric field located between two adjacent bus bar lines 42b or wiring members 142. The polar region EA1, the wiring material 142, and the third and fourth edge portions 163, 164 of the solar cell 150 and two second electrode regions EA2 located therebetween. The wiring members 142 are arranged in a plurality of positions (for example, six or more positions) on one side of the solar cell 150. Therefore, the number of first electrode regions EA1 is plural (i.e., one less than the number of the lead members 142). (number of) may be provided.

[0087] At this time, the width W2 of the first electrode region EA1 is smaller than the width W3 of the second electrode region EA2. In this embodiment, a large number of wiring members 142 or bus bar lines 42b are provided. Therefore, the inclined portions 163b and 164b of the third and fourth edges 163 and 164 are In order to position the second electrode region EA2 within the electrode region EA2, the width W3 of the second electrode region EA2 is set to a relatively small value. Therefore, the bus bar line 42b or the wiring material 142 must be large. It is possible to avoid the third or fourth edge 163, 164. However, the present invention However, the width W2 of the first electrode region EA1 and the width W3 of the second electrode region EA2 may be varied. The width W3 can have various values.

[0088] In this embodiment, the bus bar lines 42b and the wiring members 142 are arranged at uniform pitches. Therefore, the widths W2 of the first electrode regions EA1 are substantially the same. This allows the carrier to move with a uniform average moving distance, This can improve the collection efficiency of the rear.

[0089] The edge region PA corresponds to the portion where the wiring material 142 is located, and the finger electrodes 4 2a and the portion other than the first edge region PA1. The outermost finger electrode 42a and the first to fourth edge portions 161, 162 of the semiconductor substrate 160 are , 163, 164 and a second edge region PA2 spaced a certain distance apart. The first edge area PA1 is a portion of the solar cell 150 where the wiring material 142 is located. The first edge region PA1 may be located in a portion adjacent to the edge. The end of the first electrode 42 is attached to the solar cell 150 so that the first electrode 42 can be attached to the solar cell 150 with sufficient bonding strength. The area is located away from the edge of the substrate.

[0090] The first electrodes 42 are spaced apart from one another with a constant width W5 and a pitch P within the electrode area EA. The finger lines 42a may include a plurality of spaced apart finger lines 42a. 42a are parallel to each other and are connected to the main edges (particularly the first and second edges) of the solar cell 150. Although parallelism is illustrated, the present invention is not limited to this.

[0091] As an example, the finger line 42a of the first electrode 42 has a width W of 35 μm to 120 μm. 5. The finger line 42a of the first electrode 42 can have a length of 1.2 m. The pitch P may be 2.8 mm to 2.8 mm, and the direction intersecting the finger lines 42a In this case, the number of finger lines 42a may be 55 to 130. The width W5 and pitch P can be formed under easy process conditions and are generated by photoelectric conversion. While effectively collecting current, the shading loss (s The algorithm is limited to minimizing the sigma-hading loss. The thickness of the finger line 42a may be 5 μm to 50 μm. The thickness of 42a can be easily formed during the process and can have a desired resistivity. However, the present invention is not limited to this, and the finger line The width, pitch, thickness, etc. of 42a may vary depending on the process conditions, the size of the solar cell 150, the number of fingers, etc. The thickness can be varied in various ways depending on the constituent material of the line 42a.

[0092] At this time, the width W1 of the wiring material 142 is smaller than the pitch P of the finger lines 42a. , can be larger than the width of the finger line 42a. However, the present invention does not There is no limitation and various modifications are possible.

[0093] The first electrode 42 is oriented in a direction intersecting the finger line 42a within the electrode area EA. The finger lines 42a may be formed to include bus bar lines 42b connecting the finger lines 42a. For example, the bus bar line 42b extends from a portion adjacent to the first edge 161 to the second edge. As described above, the bus bar line 42 can be formed continuously to the adjacent portion. b corresponds to the portion where the wiring material 142 for connection to the adjacent solar cell 150 is located. Such bus bar lines 42b may be positioned in a one-to-one correspondence with the wiring members 142. In this embodiment, one surface of the solar cell 150 Based on this, the number of bus bar lines 42b may be the same as the number of wiring members 142. In the embodiment, the bus bar line 42b is located adjacent to the wiring material 142, and the The wiring 142 is formed in a direction perpendicular to or inclined to the wiring line 42a and is connected to or in contact with the wiring 142. It can also mean an electrode portion.

[0094] The bus bar line 42b has a relatively narrow width along the direction in which the wiring material 142 is connected. The wiring member 142 has a width greater than that of the line portion 421. The pad portion 422 may be provided to increase the connection area with the narrow line portion 42. 1, the area that blocks the light incident on the solar cell 150 can be minimized, and a wide The pad portion 422 having a large width improves the adhesion between the wiring material 142 and the bus bar line 42b. Therefore, the contact resistance can be reduced. The electrode area EA is connected to the end of the finger line 42a adjacent to the area PA1. The extension 423 may include an extension portion 423 that separates the edge region PA1 from the edge region PA2.

[0095] The pad portion 422 is an end portion of the line portion 421 (i.e., a portion where the first electrode 42 and the wiring portion 142 are connected). The first pad portion 422a is located at the end of the first pad portion 422a. However, it may include a second pad portion 422b located in the inner region of the bus bar line 42b. As described above, the wiring material 1 is electrically connected to the end of the line portion 421 or the first pad portion 422a. A force is applied to the first electrode 42 in a direction away from the first electrode 42 (a direction away from the semiconductor substrate 160). This allows the area of ​​the first pad portion 422a to be increased by the area of ​​the second pad portion 422. b, so that the wiring material 142 and the first electrode 42 have a strong adhesive force. At this time, the width of the first pad portion 422a is set to be larger than the width of the second pad portion 422b. Even if the thickness is reduced, it is difficult to significantly improve the adhesive strength with the wiring material 142. The length L1 of the second pad portion 422a (measured in the longitudinal direction of the wiring material 142) is 22b (length measured in the longitudinal direction of the wiring material 142) L2. can.

[0096] The width of the pad portion 422 (more specifically, the width of the first pad portion 422a and the width of the second pad portion 422b) The widths of the line portions 421 and the finger lines 42a are set to be larger than the widths of the line portions 421 and the finger lines 42a. The pitch of the bus bar lines 42b is smaller than the pitch of the finger lines 42a. can also be made larger.

[0097] In this embodiment, the line portion 4 of the bus bar line 42b is formed so as to correspond to the wiring material 142. More specifically, in the existing one, the wiring material 142 is provided with In response, a bus bar electrode having a width much larger than that of the finger line 42a is positioned. However, in this embodiment, the width of the bus bar line 42b is much smaller than that of the bus bar electrode. In this embodiment, the line portion 421 is formed by a plurality of finger lines 4 By connecting 2a, carriers can be bypassed when some finger lines 42a are disconnected. A route that can be taken around the area can be provided.

[0098] In this specification, the busbar electrodes are intersecting finger lines to correspond to ribbons. It is formed in the direction of the finger line and has a width of 12 times or more (usually 15 times or more) the width of the finger line. The busbar electrode has a relatively large width, so it is usually about 2 to 100 mm thick. In this embodiment, the line portion 421 of the bus bar line 42b is formed as a wiring The finger line 42a is formed in a direction intersecting the finger line 42a so as to correspond to the finger This may mean an electrode portion having a width 10 times or less than the width of the line 42a.

[0099] For example, the width W4 of the line portion 421 is 0.5 to 1 / 2 times the width W5 of the finger line 42a. If the ratio is less than 0.5, the width of the line portion 421 becomes small. Therefore, the effect of the line portion 421 may not be sufficient. In this case, the width of the line portion 421 increases, which may increase the optical loss. Since a large number of wires 142 are provided, a large number of line portions 421 are also provided, and the optical loss is further increased. More specifically, the width W4 of the line portion 421 can be set to be equal to or smaller than the width W of the finger line 42a. The ratio may be 0.5 to 7 times 5. By setting the ratio to 7 times or less, the optical loss can be further reduced. As an example, in terms of optical loss, the width W4 of the line portion 421 is The width W5 of the line portion 42a may be 0.5 to 4 times. The width W4 of the finger line 21 may be 0.5 to 2 times the width W5 of the finger line 42a. In such a range, the efficiency of the solar cell 150 can be significantly improved.

[0100] Alternatively, the width W4 of the line portion 421 is equal to or smaller than the width W1 of the lead 142. When the wiring member 142 has a circular, oval, or round shape, Since the width or area of ​​the lower part of 42 that contacts the line part 421 is not large, This is because the width W4 can be made equal to or smaller than the width W1 of the lead 142. In this way, when the width W4 of the line portion 421 is relatively small, the area of ​​the first electrode 42 is reduced. By reducing the amount of the first electrode 42, the material cost of the first electrode 42 can be reduced.

[0101] For example, the ratio of the width W1 of the wiring member 142 to the width W4 of the line portion 421 is 1:0.07 to 1:0.07. If the ratio is less than 1:0.07, the width of the line portion 421 becomes small. If the ratio is too low, the electrical properties may be degraded. The contact characteristics with the inner portion 421 cannot be significantly improved, and the area of ​​the first electrode 42 This increases the amount of light, which leads to problems such as increased optical loss and increased material costs. Considering the optical loss, material cost, etc., the ratio is 1:0.1 to 1:0.5 (more Specifically, it may be 1:0.1 to 1:0.3).

[0102] Alternatively, the width W4 of the line portion 421 may be 35 μm to 350 μm. If the width W4 of the line portion 421 is less than 35 μm, the width of the line portion 421 is too small, and the electrical characteristics are poor. If the width W4 of the line portion 421 exceeds 350 μm, the line The contact characteristics with the first electrode 421 cannot be significantly improved, and only the area of ​​the first electrode 42 is This increases the optical loss and increases the material cost. When further consideration is given to loss, material cost, etc., the width W4 of the line portion 421 is set to 35 μm to 200 μm. m (more specifically, 35 μm to 120 μm).

[0103] However, the present invention is not limited to this. 4 effectively transmits the current generated by photoelectric conversion while minimizing shading loss. Various modifications are possible within the scope of minimization.

[0104] The width W6 of the pad portion 422 is larger than the width W4 of the line portion 421. The width W1 of the pad portion 422 may be equal to or greater than the width W1 of the wiring material 142. This is a part for increasing the contact area and improving the adhesive strength with the wiring material 142. The width of the wiring member 142 is larger than that of the wiring member 421 and is equal to or larger than that of the wiring member 142. That is why.

[0105] For example, the ratio of the width W1 of the wiring member 142 to the width W6 of the pad portion 422 is 1:1 to 1:5. If the ratio is less than 1:1, the width W6 of the pad portion 422 may be insufficient. Therefore, the adhesive strength between the pad portion 422 and the wiring material 142 may be insufficient. If the value exceeds 5, the area where light loss occurs due to the pad portion 422 increases, resulting in shading. Considering the adhesive strength, light loss, etc., the ratio of 1:2 It may be 1:4 or less (more specifically, 1:2.5 to 1:4).

[0106] Alternatively, for example, even if the width W6 of the pad portion 422 is 0.25 mm to 2.5 mm, If the width W6 of the pad portion 422 is less than 0.25 mm, the contact area with the wiring material 142 becomes If this is not sufficient, the adhesive strength between pad portion 422 and wiring material 142 may be insufficient. If the width W6 of the pad portion 422 exceeds 2.5 mm, optical loss occurs due to the pad portion 422. As an example, the area of ​​the pad portion 42 may increase, resulting in a large shading loss. The width W6 of the second portion may be 0.8 mm to 1.5 mm.

[0107] The lengths L1 and L2 of the pad portion 422 are greater than the width of the finger line 42a. For example, the lengths L1 and L2 of the pad portion 422 can be set to 0.035 mm to 30 mm. If the lengths L1 and L2 of the pad portion 422 are less than 0.035 mm, Since the contact area with the wiring material 142 is insufficient, the adhesive strength between the pad portion 422 and the wiring material 142 is low. If the length of the pad portion 422 exceeds 30 mm, the pad portion 422 This increases the area where light loss occurs, which can increase shading loss.

[0108] At this time, the length L1 of the first pad portion 422a to which a larger force is applied is set to the length L2 of the second pad portion 422b. The length L2 of the first pad portion 422b can be made larger than the length L2 of the first pad portion 422b. The length L1 of 22a may be 0.4 mm to 30 mm, and taking into consideration the optical loss, The length L1 of the first pad portion 422a may be 0.4 mm to 3.2 mm. The length L2 of 422b may be 0.035 mm to 1 mm, more specifically 0.4 mm This allows the first pad portion 422a to be subjected to a large force. The adhesive force is further improved by the second pad portion 422b, and the area of ​​the second pad portion 422b is reduced, thereby reducing light loss. It is possible to reduce material costs, etc. However, the present invention is not limited to this. Alternatively, the width of the first pad portion 422a may be greater than the width of the second pad portion 422b. The width and length of the first pad portion 422a are respectively equal to the width and length of the second pad portion 422b. The length may be greater than each of the lengths.

[0109] Alternatively, for example, the width W5 of the finger line 42a: the length L1 of the pad portion 422, The ratio of L2 may be 1:1.1 to 1:20. 2 and the wiring material 142 is increased, and the adhesion area between the pad portion 422a and the wiring material 142 is increased. You can improve your strength.

[0110] Alternatively, for example, the ratio of the width W1 of the wiring material 142 to the lengths L1 and L2 of the pad portion 422 is If the ratio is less than 1:1, the pad portion 422 Since the lengths L1 and L2 are not sufficient, the adhesive strength between the pad portion 422 and the wiring material 142 is not sufficient. If the ratio exceeds 1:10, the pad portion 422 may cause optical loss. The area covered by the adhesive increases, which can lead to increased shading loss. Taking this into consideration, the ratio may be 1:3 to 1:6.

[0111] In one bus bar line 42b, there are 6 to 24 pad portions 422 (for example, The pad portions 422 may be arranged at intervals. For example, one may be positioned for every 2 to 10 finger lines 42a. In this way, the bonding area between the bus bar line 42b and the wiring material 142 is increased. By providing the portions regularly, the adhesion between the bus bar line 42b and the wiring material 142 can be improved. Alternatively, the distance between the two pad portions 422 may be different from each other. In particular, a plurality of pad portions 422 may be arranged on other portions (i.e., bus bar lines). At the end of the bus bar line 42b, a larger force is applied than at the center of the bus bar line 42b. The head portions 422 may be arranged at a high density. Various other modifications are possible.

[0112] Referring again to FIG. 7, the width W1 of the wiring member 142: the width of the wiring member 142 adjacent to the pad portion 422 The coating layer 142b (a separate bonding layer for bonding the wiring material 142 and the pad portion 422) When a bonding layer (for example, a soldering layer) is located, the bonding layer is located between the pad portion 422 and the bonding layer. The ratio of the width W7 of the adhesive layer (which is formed by the adhesive layer) to the width W7 of the adhesive layer (which is formed by the adhesive layer) may be 1:1 to 1:3.33. However, the ratio is not limited thereto and may have various values.

[0113] The width of the pad portion 422 is determined by the coating thickness of the portion adjacent to the pad portion 422. The width W7 of the layer 142b may be equal to or greater than the width W7 of the pad portion 422. Ratio of width W7 of coating layer 142b in adjacent portion to width W6 of pad portion 422 If the ratio is less than 1:1, the wiring material 142 and the If the ratio exceeds 1:4.5, the adhesive property with the pad portion 422 is not excellent. The area of ​​the portion 422 becomes large, which may increase light loss and manufacturing costs.

[0114] However, the present invention is not limited to this. 1, L2 increases the contact area with the wiring material 142 to improve the adhesive force with the wiring material 142. The pad portion 422 may have various values ​​within a range that can be achieved. It is also possible not to provide it.

[0115] Referring again to FIG. 9, the bus bar line 42b is connected to the end of the line portion 421. The electrode area EA and the first edge area PA1 may include an extension 423. The portion 423 connects the ends of the finger lines 42a adjacent to the first edge region PA1. When the extension portion 423 is provided, the finger loop adjacent to the first edge region PA1 can be When there is a break in the power supply 42a, it provides a path for carriers to flow. vinegar.

[0116] The extension portion 423 extends from the first edge portion 161 or the second edge portion 162 of the solar cell 150. The finger lines 42a and the bus bar lines 42b are arranged so that the width of the edge region PA1 gradually increases. For example, the first edge region PA1 may have a substantially triangular shape. The first edge region PA1 may have two extensions 423 that are substantially "V-shaped." This allows the two electrode regions adjacent to the first edge region PA1 to In the EA, the outer ends of the finger lines 42a are arranged to be increasingly farther apart from each other. The first edge area PA1 can be formed between the two electrode areas EA. The width of the first or second edge 161, 162 of the groove 160 may be increased. As a result, the width of the end of the electrode area EA adjacent to the first edge area PA1 is smaller than that of the other areas. As an example, the first edge area PA1 may have an isosceles triangle shape. Each electrode area EA may have a generally octagonal shape.

[0117] As a result, the lead 142 is not attached to the extension 423 but is disposed within the first edge region PA1. In this embodiment, the solar cell 150 is not connected to other solar cells 150. One end of the thin wiring member 142 (the upper end in FIG. 9) is connected to one end of the line portion 421 (the upper end in FIG. 9). The wiring member 142 extends through the line portion 142a to the inside of the first edge region PA1. 421 and the edge of the solar cell 150 adjacent thereto (i.e., the first edge 161). The wiring can be located inside the first edge region PA1 located between the wiring. The material 142 can be stably fixed to one end of the line portion 421, and the first pad portion 422 On the other hand, the wiring material 142 can be fixed to the first electrode 42 with sufficient adhesive force due to the adhesive force a. The end is located at the end of the line portion 421 or does not reach one end of the line portion 421. In this case, one end of the wiring member 142 is connected to the first pad portion 422 located at one end of the line portion 421. Alternatively, the wiring material 142 may not be stably attached to the second edge region PA2. If the wire is extended too far, problems such as unnecessary short circuits may occur.

[0118] The other end of the lead 142 (the lower end in FIG. 9) is connected to the other end of the line portion 421, The busbars of the adjacent solar cells 150 pass through the edge region PA1 and the second edge region PA2. It is connected to line 42b.

[0119] As an example, in the first edge region PA1, the wiring located within the first edge region PA1 The length of the wiring material 142 may be longer than the length of the portion where the wiring material 142 is not located. That is, the ratio of the length L3 of the first edge region PA1 to the length L4 of the first edge region PA1 is 1: The ratio may be 0.5 to 1:1. This allows the wiring 142 to be stably attached to the first pad portion 422a. More specifically, the length L3 of the first edge region PA1: The ratio of the length L4 of A1 to the length L4 of A2 may be 1:0.6 to 1:0.9. The wiring material 142 is stably attached to the first pad portion 422a and extends to the second edge region PA2. However, the present invention is not limited to this.

[0120] At this time, the wiring material 142 is attached to the bus bar line 42b and positioned in the first edge region. The wiring material 14 may be located in the area PA1 without being attached to the solar cell 150. The coating layer 142b containing the solder material in 2 is formed on the bus bar line 42b (particularly, It is often attached to the pad portion 422, but in the area where the bus bar line 42b is not located. This is because it is difficult to adhere.

[0121] The width W of the first edge region PA1 located between the outermost finger lines 42a 8 can be made larger than the width of the wiring material 142. In particular, the wiring material 142 can be stably positioned within the first edge area PA1. Even when the wiring material 142 bends left or right in the first edge region PA during the wiring process, It may be located within the first edge area PA.

[0122] The width W8 of the first edge region PA1 may be 0.73 mm to 3.8 mm. The width W8 of the first edge region PA1 may be 0.73 mm to 2 mm. The ratio of the width W1 of the wire 142 to the width of the first edge region PA1 is 1:1.46 to 1:15.2 ( For example, the ratio may be 1:1.46 to 1:5. Within this range, stable distribution is possible. The wire 142 may be located within the first edge region PA.

[0123] Alternatively, when the width W8 of the first edge region PA1 is L and the edge distance D is D, L and D are , the following equation 1 can be satisfied: where the edge distance D is the distance between the first electrode 42 and the edge of the first electrode 42. In this case, the end of the first electrode 42 and the edge of the solar cell 150 (more specifically, the first or second edge 1 61,162).

[0124]

number

[0125] (Here, the unit of L is mm and the unit of D is mm.)

[0126] This is because the larger the edge distance D, the more likely it is that the wiring material 142 will bend. Therefore, the larger the edge distance D, the more the width W8 of the first edge region PA1 needs to be secured. However, the present invention is not limited to this.

[0127] The width of the extension portion 423 is smaller than the width of the line portion 421. The width of the extension 423 may be twice or more than the width of the line portion 421. The sum of the widths of the two extensions 423 at the branched portion is the same as the width of the line portion 421. This minimizes the width of the extension portion 423 and the line portion 421. The width of bus bar line 42b is increased at the portion where two extension portions 423 are connected. For example, the width W4 of the line portion 421 can be set to be equal to the width of the extension portion 423. Alternatively, for example, the line width of the extension 423 may be 35 μm to 10 times. It may be 20 μm.

[0128] Alternatively, the width of the extension 423 is smaller than the width of the finger line 42a, or The extension 423 may be the same as or substantially the same as the finger line 42a. The width of the finger line 42a is equal to or less than twice the width of the finger line 42a (for example, 0.5 to 2 times). This allows the effect of the extension 423 to be realized, and also the effect of the extension 423 to be realized. This can prevent problems such as an increase in optical loss. However, the present invention is not limited to this. Instead, the width of the extension 423 is set to connect the finger lines 42a so that a current can flow. It is sufficient if the range is wide enough.

[0129] In this embodiment, the thickness of the bus bar line 42b may be 3 μm to 45 μm. Such a thickness of the bus bar line 42b can be easily formed during the manufacturing process and has a desired resistivity. However, the present invention is not limited to this. The thickness of the bus bar 42b may vary depending on the process conditions, the size of the solar cell 150, and the bus bar The thickness can be varied depending on the material of the line 42b.

[0130] In this embodiment, the finger lines 42a and the bus bar lines 42b are different from each other. For example, as shown in the enlarged upper circle of FIG. b is formed first, and then the finger line 42a is connected to at least a part of the bus bar line 42b. In this embodiment, the bus bar line 42b can be formed so as to extend over the The finger line 42a is located on one side (for example, the left side of the figure) as a reference, and the finger line 42b is located on the other side (for example, For example, the finger line 42a located on the right side of the figure is spaced apart from the finger line 42a. As shown, if there is a portion on the bus bar line 42b where the finger line 42a is not formed, This can minimize the manufacturing cost when forming the finger lines 42a. The present invention is not limited to this, and the finger line 42a may be connected to the bus bar line 42. It is also possible for the ion beam to be positioned across the entirety of b.

[0131] The finger lines 42a and the bus bar lines 42b may be made of the same material. For example, the finger lines 42a and the bus bars 42b may be made of different materials. When the bus bar line 42b is formed by printing, a printing plate for forming the bus bar line 42b is used. The paste for forming the finger lines 42a has a relatively low viscosity. It can have a relatively high viscosity, which allows the bus bar line 42b to be The thickness of the finger line 42a may be greater than the thickness of the In addition, if the bus bar line 42b is formed first and then the finger line 42a is formed, It can be formed more stably.

[0132] As an example, a metal (e.g., silver) of the paste for forming the finger line 42a may be used. is the metal (e.g., silver) content of the paste for forming the bus bar line 42b. This allows the finger line directly related to carrier collection to be 42a can be reduced to improve the carrier collection efficiency, and the busbar line 4 The content of metal in 2b can be reduced to reduce the manufacturing cost.

[0133] At this time, the finger lines 42a of the first electrode 42 are in contact with the passivation film 22 and the reflecting film 23. The bus bar line 42b is formed through the passivation film 22 and the anti-reflection film 24. In this case, the opening (reference numeral 102 in FIG. 3) may be formed on the anti-reflection film 24. The part where the sub-line 42b is not positioned is shaped to correspond to the finger line 42a. It is not necessary to form the wiring layer 42a in the area where the bus bar line 42b is located. The first conductivity type region 20 may have a shape corresponding to the portion where the opening 102 is formed. That is, the first conductivity type region 20 corresponds to the finger line 42a in the electrode region EA. The wiring conductors 42a and 42b are not formed in the portions corresponding to the bus bar lines 42b. In this case, the line portion 421 and the pad portion 4 22 and an extension 423 are formed on the passivation film 22 and the anti-reflection film 24, The first conductivity type region 20 does not need to be formed in the corresponding portion. The line portion 421, the pad portion 422 and the extension portion 423 constituting the line 42b are floating. (floating) electrodes can be configured.

[0134] However, the present invention is not limited to the above, and the finger lines 42a may be formed first. Alternatively, the bus bar line 42b may be formed after the wiring is completed. As shown, the finger lines 42a and the bus bar lines 42b are bonded together in one process. The layers may be formed of the same material. is possible.

[0135] The first electrode 42 is connected to the end of the finger line 42a, and the third and fourth edges The electrode area EA and the second edge area PA2 are separated in the portion adjacent to 163 and 164. The edge line 42c may include an edge line 42c extending from the third and fourth edges 1. The portions adjacent to the third and fourth edges 163, 164 are spaced apart at uniform intervals. and have the same or nearly the same shape as the third and fourth edges 163, 164. At this time, the edge line 42c is adjacent to the third and fourth edges 163 and 164. The ends of the finger lines 42a are connected to each other.

[0136] Between the third and fourth edges 163, 164 and the edge line 42c, and between the first and second edges 163, 164 and the edge line 42c, A uniform width is provided between the edges 161, 162 and the outermost finger line 42a. The second edge area PA2 may be formed in a frame shape. The width W9 of the second edge region PA2 may be 0.5 mm to 1.5 mm. If W9 is less than 0.5 mm, problems such as unnecessary shunting may occur. 2 If the width of the edge area PA2 exceeds 1.5 m, the area of ​​the ineffective area will become large. However, the efficiency of the solar cell 150 may not be high. However, the present invention is not limited to this. isn't it.

[0137] The width of the edge line 42c may be the same as or approximately the same as the finger line 42a. The width and thickness of the finger line 42a, the relationship between the other electrode parts and the wiring material 142, etc. This can also be applied to the edge line 42c as is.

[0138] In this embodiment, the width W1 of the wiring member 142 is W, and the width W2 of the wiring member 142 is The edge of the first electrode 42 and the edge of the solar cell 150 (more specifically, the first or second edge 161, 162) is D, the edge distance D between the W and the D satisfies the following formula 2. It is possible.

[0139]

number

[0140] (Where, the unit of W is μm and the unit of D is mm.)

[0141] As described above, at the end of the first electrode 42 where the wiring material 142 is located, the solar cell 150 A force is applied to the wiring member 142 in a direction away from the first electrode 42, and the adhesive force between the wiring member 142 and the first electrode 42 That is, as shown in FIG. 11, when the width W1 of the lead 142 is large, As the temperature decreases, the degree to which the solar cell 150 or the semiconductor substrate 160 bends increases. 11 indicates that the width W1 of the wiring material 142 is 300 μm. , 330wire is when the width W1 of the wiring material 142 is 330 μm, and 400wi re means that the width W1 of the wiring material 142 is 400 μm. When the width W1 of the wiring material 142 is increased, the solar cell 1 is attached to the wiring material 142 at the end of the first electrode 42. A larger force acts in the direction away from 50, which causes the first electrode In order to prevent such a decrease in adhesive strength, In the embodiment, by ensuring a sufficient edge distance D, the stress applied to the first electrode 42 is minimized. To make smaller.

[0142] That is, the inventors have found that as the width W1 of the wiring material 142 increases, the edge distance D also increases. It was found that the adhesive strength between the lead 142 and the first electrode 42 was sufficient only when the adhesive strength was increased. The range of the edge distance D according to the width W1 of the wiring material 142 is presented as Equation 2. is.

[0143] More specifically, the inventors have changed the width W1 and the edge distance D of the lead 142. The adhesive strength of the wiring material 142 at the end of the first electrode 42 was measured. Search for cases with values ​​above (e.g., values ​​of 1.5N or more (more preferably, 2N or more)). This is shown in Figure 12 by the x symbol. The range of the edge distance D according to the width W1 of the wiring material 142 is included so that the portion can be included. The above-mentioned formula 2 for the lower and upper limits of the edge distance was derived by searching for the part where the edge distance is smaller than the upper limit.

[0144] Therefore, when the width W1 of the lead 142 has a certain value, the edge distance D is If the value falls within the range of Equation 2, the wire-shaped wiring material 142 is connected to the end of the first electrode 42. Therefore, according to this embodiment, the wire can be stably attached. By using the wiring material 142 having an ear shape, various effects are realized and The adhesion of the lead 142 can be improved by adjusting the edge distance D.

[0145] At this time, since the width W1 of the wiring material 142 is 250 μm to 500 μm, the edge distance D More specifically, the value of the wiring material 1 can be 2.37 mm to 21.94 mm. When the width W1 of 42 is 250 μm or more and less than 300 μm, the edge distance D is 2.37 m The width W1 of the wiring material 142 may be 300 μm or more and 350 μm or less. When the wiring material is less than 1.0 mm, the edge distance D may be 3.99 mm to 12.94 mm. When the width W1 of 142 is 350 μm or more and less than 400 μm, the edge distance D is 5.06 The width W1 of the wiring material 142 may be 400 μm or more and 450 μm or more. When the thickness is less than 1 μm, the edge distance D may be 5.69 mm to 18.96 mm. When the width W1 of the wire 142 is 450 μm to 500 μm, the edge distance D is 5.94 mm. In this range, the above-mentioned formula 2 is satisfied and an excellent It can have adhesive properties.

[0146] For example, when the width W1 of the wiring material 142 is 250 μm or more and less than 300 μm, The edge distance D may be 4 mm to 9.78 mm. When the thickness is 350 μm or more and less than 350 μm, the edge distance D may be 6 mm to 12.94 mm. When the width W1 of the wiring material 142 is 350 μm or more and less than 400 μm, the edge distance D The width W1 of the wiring material 142 may be 400 μm or more, and the width W2 may be 9 mm to 15.98 mm. When it is less than 50 μm, the edge distance D may be 10 mm to 18.96 mm. When the width W1 of the wire 142 is 450 μm to 500 μm, the edge distance D is 12 mm to 2 In this range, sufficient adhesive strength can be obtained more stably. In particular, in this embodiment, the width W1 of the wiring material 142 is 350 μm or more, and 400 μm or less. When the distance D is less than 9 mm, the edge distance D may be 9 mm to 15.98 mm. The output of the battery panel 100 can be maximized. However, the present invention is not limited to this. It's not something like that.

[0147] As an example, the edge distance D is set to the width W2 of the first electrode region EA1 (i.e., the distance between two adjacent electrodes). the distance or pitch between the sub-lines 42b or the wiring material 142, and the second electrode region The width W3 of the area EA2 (i.e., the width of the bus bar line 42b or wiring adjacent to the edge of the solar cell 150) The distance between the wire 142 and the edge of the solar cell 150 may be smaller than the distance between the wire 142 and the edge of the solar cell 150. Therefore, the edge distance D can be limited so that the carrier collection efficiency can be improved. However, the present invention is not limited to this.

[0148] At this time, in this embodiment, the wiring material 142 is located at the end of the bus bar line 42b. Since the first pad portion 422a is located on each side, the first pad portion 422a and the solar cell 15 The edge distance D between the first and second edges 161, 162 of 0 is within the range of the above-mentioned formula 2. You can be satisfied.

[0149] The inventors have determined that the number of wiring members 142 (or bus bar lines) located on one surface of the solar cell 150 It was also found that the number of wiring layers 42b has a certain relationship with the width W1 of the wiring material 142. The output of the solar cell panel 100 measured while varying the width W1 and number of wiring members 142 6 to 33 wiring members 142 each having a width W1 of 250 μm to 500 μm are arranged. It can be seen that when these are provided, the output of the solar cell panel 100 has an excellent value. When the width W1 of the wiring material 142 is increased, the number of wiring materials 142 required can be reduced. You can see that it is possible.

[0150] For example, when the width W1 of the wiring material 142 is 250 μm or more and less than 300 μm, The number of wiring members 142 (the number of wiring members 142 when one surface of the solar cell 150 is used as a reference) is 15 to 3 The width W1 of the wiring material 142 is equal to or greater than 300 μm and less than 350 μm. The number of wiring members 142 may be 10 to 33. When the thickness is equal to or greater than 400 μm and less than 400 μm, the number of wiring members 142 may be 8 to 33. When the width W1 of the wiring members 142 is 400 μm to 500 μm, the number of the wiring members 142 is six. The number of wiring members 142 may be 33 to 33. When the width W1 of the wiring member 142 is 350 μm or more, the number of wiring members 142 may be 33 to 33. Even if the number of wires 142 exceeds 15, the output of the solar cell panel 100 is unlikely to increase any further. Furthermore, if the number of wiring members 142 is large, it may place a burden on the solar cell 150. Taking this into consideration, when the width W1 of the wiring material 142 is 350 μm or more and less than 400 μm, The number of wiring members 142 may be 8 to 15. The width W1 of the wiring members 142 is 400 μm. When the thickness is 1 / 2 to 500 μm, the number of wiring members 142 may be 6 to 15. In order to further improve the output of the solar cell panel 100, the number of wiring members 142 is set to 10 or more ( For example, 12 to 13 of the number of the hydroxyl groups may be included. However, the present invention is not limited to this. Instead, the number of wiring members 142 and the number of bus bar lines 42b have different values. You may do so.

[0151] At this time, the pitch of the wiring material 142 (or the pitch of the bus bar line 42b) is 4.75 m. This is in consideration of the width W1 and number of the wiring members 142. For example, when the width W1 of the wiring material 142 is 250 μm or more and less than 300 μm, The pitch of the wiring members 142 may be 4.75 mm to 10.45 mm. When the width W1 of the wiring material 142 is 300 μm or more and less than 350 μm, the pitch of the wiring material 142 is 4.7 The width W1 of the wiring material 142 may be 350 μm or more and 40 When the pitch of the wiring material 142 is less than 4.75 mm to 19.59 mm, When the width W1 of the wiring member 142 is 400 μm to 500 μm, the pin The pitch of the wiring material 142 may be 4.75 mm to 26.13 mm. When the width W1 is 350 μm or more and less than 400 μm, the pitch of the wiring material 142 is 10.4 The width W1 of the wiring material 142 may be 400 μm to 500 μm. m, the number of wiring members 142 may be 10.45 mm to 26.13 mm. However, the present invention is not limited to this, and the pitch of the wiring material 142 and the resulting barrier The pitch of the spine lines 42b may have different values.

[0152] In this embodiment, the first electrode 42, the wiring member 142, the electrode area EA, the edge area PA, etc. The left-right direction (the direction parallel to the finger line 42a) and the up-down direction (the bus bar line 42b Alternatively, they may be positioned symmetrically with respect to each other in a direction parallel to the wiring material 142. Therefore, the current flow can be stably realized. However, the present invention is not limited to this. It's not something like that.

[0153] As described above, one end of the bus bar line 42b (for example, the upper end in FIG. 9) and / or the other end (for example, the lower end in FIG. 9) and the edge of the solar cell 150 adjacent thereto (i.e., the first and / or second edges 161, 162) have a sufficient edge distance D As a result, one end of the bus bar line 42b in the extension direction of the bus bar line 42b and The distance between the other end of the bus bar line 42b and the other end of the bus bar line 42b is Finger line located on the outermost side of one of 2a (finger line at the top of the figure) 4 2a and the other outermost finger line (the lowermost finger line in the figure) 42 a. The distance between the edge and the edge is shorter than the distance between the edge and the edge. The effect can be fully realized.

[0154] In the above description, the first electrode 42 has been mainly described with reference to FIGS. The electrode 44 includes the finger line 42a, the bus bar line 42b, the edge line 42a, and the The finger lines, bus bar lines, and edge lines corresponding to the 42c are included. The finger lines 42a, bus bar lines 42b, and edge lines of the first electrode 42 can be The contents of the line 42c are the finger line and bus bar line of the second electrode 44. , can be applied to the edge line. At this time, the first conductivity type associated with the first electrode 42 The description of region 20 is a description of second conductivity type region 30 associated with second electrode 44. The first passivation film 22 and the anti-reflection film 2 associated with the first electrode 42 may be formed. 4, and the description of the opening 102 is related to the second passivation associated with the second electrode 44. This may be a description of the silicon membrane 30 and the opening 104.

[0155] At this time, the line portions of the finger lines 42a and bus bar lines 42b of the first electrode 42 The width, pitch, number, etc. of the pad portions 421 and 442 are determined based on the finger line 4 of the second electrode 44. 4a, the width, pitch, number, etc. of the line portion and pad portion of the bus bar line 44b are the same as each other. Alternatively, the finger lines 42a of the first electrode 42 and the bus bar lines 42 The width, pitch, number, etc. of the line portion 421 and the pad portion 442 of b are determined based on the fins of the second electrode 44. Width, pitch, number, etc. of the line and pad portions of the gar line 44a and bus bar line 44b For example, the potential of the second electrode 44, which receives relatively less light, may be different from that of the first electrode 44. The width of the pole portion may be larger than the width of the corresponding electrode portion of the first electrode 42, and the width of the second electrode The pitch of the electrode portions 44 may be smaller than the pitch of the corresponding electrode portions of the first electrode 42. However, the number and shape of the bus bar lines 42b of the first electrode 42 may be varied. The number and pitch of the busbar lines of the second electrode 44 may be the same as the number and pitch of the busbar lines of the second electrode 44, respectively. In addition, the first electrode 42 and the second electrode 44 may have different planar shapes. Many variations are possible.

[0156] According to this embodiment, the wiring material 142 in the form of a wire is used to reduce optical loss due to diffuse reflection or the like. The pitch of the wiring material 142 can be reduced to minimize the carrier movement path. This can improve the efficiency of the solar cell 150 and the solar panel 100. At this time, the output of the first electrode 42 can be improved depending on the width of the wiring material 142. The bonding strength between the wiring material 142 having a wire shape and the first electrode 42 is increased by limiting the edge distance D. As a result, when the lead 142 is separated from the first electrode 42, This prevents damage to the solar cell 150 that may occur due to the heat generated by the heat generated by the solar cell 150, and allows the solar cell 150 to have excellent electrical characteristics. The wiring material 142 has a width W1, and can have excellent reliability. By limiting the number of wiring members 142, the output of the solar cell panel 100 can be maximized.

[0157] Hereinafter, a solar cell and a solar cell including the same according to another embodiment of the present invention will be described with reference to the accompanying drawings. The battery panel will be described in detail. For parts that are the same as or very similar to the above description, the same reference will be made to the above. The above explanation can be applied as it is, so we will omit detailed explanations and only explain the differences. The above-mentioned embodiment or its modified example and the following embodiment or Combinations of these modified examples are also within the scope of the present invention.

[0158] FIG. 14 is a partial front plan view of a solar cell according to another embodiment of the present invention.

[0159] Referring to FIG. 14, in this embodiment, between two adjacent bus bar lines 42b The finger line 42a is not connected continuously but has a broken portion S. It can be prepared.

[0160] At this time, the disconnection portion S is formed in the finger line 42a located in the first electrode region EA1. However, it may not be formed on the finger lines 42a located in the second electrode region EA2. In the first electrode region EA1, even if the finger line 42a has a disconnection portion S, the finger Since the line 42a is connected to one bus bar line 42b or wiring material 142, the current This allows the current to flow smoothly, thereby preventing the current from flowing in the first electrode region EA1. Since the area of ​​the first electrode 42 can be reduced without increasing the manufacturing cost and the optical loss, In the second electrode region EA2, the bus bar line 42b is provided only on one side. Alternatively, since the wiring material 142 is connected, the bus bar located on one side does not have a disconnection portion S. This allows current to flow smoothly to the wiring 42b or the wiring material 142.

[0161] The broken portion S of the finger line 42a is located between two adjacent bus bar lines 42b. This can minimize the path of current travel.

[0162] The width of the disconnection portion S may be 0.5 times or more the pitch of the finger lines 42a. The width of the broken portion S may be 0.5 times or less the pitch of the sub-lines 42b. If the pitch of the line 42a is less than 0.5 times, the width of the disconnected portion S is narrow, and therefore, the disconnected portion S When the width of the broken portion S is 0.5 times the pitch of the bus bar line 42b, the effect of If it exceeds 100 times, the width of the disconnection part S will increase, which may result in a deterioration of the electrical characteristics. As an example, the width of the disconnection portion S may be 1.5 mm to 1.8 mm. The width of the disconnection portion S may be larger than the width W6 of the pad portion 422 of the bus bar line 42b. Within this range, the effect of the disconnection portion S can be maximized. The width of the disconnection portion S is not limited to this, and may have various values.

[0163] In each first electrode area EA1, the field strength measured in a direction parallel to the bus bar line 42b is The ratio of the number of finger lines 42a with disconnection portions S to the number of finger lines 42a The effect of the disconnection part S can be maximized within this range. As an example, in this embodiment, two adjacent bus bar lines 42b can be The finger line 42a to be connected and the finger line 42a having the disconnection portion S are one. This allows for a sufficient number of disconnected portions S and also allows for the The average moving distance can be minimized. However, the present invention is not limited to this. The ratio of the numbers mentioned above may vary.

[0164] In the figure, each of the first electrode regions EA1 is provided with a disconnection portion S. However, the present invention is not limited to this. The other portions may not have the disconnected portion S. Although the above description has been given with reference to the first electrode 42, such description may be applied to the second electrode 44. may be applied as is.

[0165] FIG. 15 is a partial front plan view of a solar cell according to yet another embodiment of the present invention.

[0166] Referring to FIG. 15, in this embodiment, between two adjacent bus bar lines 42b The finger lines 42a may have different widths. The inner wall 42a has a narrow portion S1 having a relatively narrow width and a wide portion S2 having a relatively wide width. It is possible.

[0167] As an example, in this embodiment, the finger line 42a located in the first electrode region EA1 is A finger line 42 including a narrow portion S1 and a wide portion S2 and located in the second electrode region EA2. a may be formed to have a uniform width (for example, the same width as the widened portion S2). In the area EA1, the finger line 42a is connected to two adjacent bus bar lines 42b or Since the first electrode 142 is connected to the wire 142, the current can flow smoothly. The narrow portion S1 of the first electrode 42 allows the first electrode 42 to pass through the first polar region EA1 without interfering with the flow of current therethrough. The area of ​​the electrode 42 can be reduced, which reduces manufacturing costs and optical loss. In the second electrode region EA2, the bus bar line 42b or the wiring material 1 is provided only on one side. 42 is connected, and therefore has a uniform width by not having a narrow width portion S1. The current can flow smoothly to the bus bar line 42b or the wiring material 142 located at Do so.

[0168] In this embodiment, the narrow portion S1 of the finger line 42a is formed between two adjacent bus bars. The bus bar 42b is located in the center between the bus bar 42b and extends toward each of the two bus bar lines 42b. The width of the finger line 42a can be gradually increased by this. However, the present invention is not limited to this, and the narrow width portion S1 and the wide width portion S2 may be formed as follows. The finger line 42a having the width portion S2 can have various shapes.

[0169] In each first electrode area EA1, the field strength measured in a direction parallel to the bus bar line 42b is The ratio of the number of finger lines 42a with narrow portions to the number of finger lines 42a is The width may be 0.33 to 1. Within this range, the effect of the narrow portion is maximized. However, the present invention is not limited to this, and the ratio of the number of pieces can be It can change.

[0170] In the figure, each of the first electrode regions EA1 is provided with a narrow portion S1. The embodiment is not limited to this. A narrow width portion S1 is formed in a part of the plurality of first electrode regions EA1. The narrow width portion S1 may be provided in the other portions, and the narrow width portion S1 may not be provided in the other portions. The line portions S may be mixed. In the drawings and the above description, the first electrode 42 However, this description may be applied to the second electrode 44. do.

[0171] The present invention will be described in more detail below with reference to experimental examples. It is provided for illustration purposes only and is not intended to limit the invention.

[0172] Experimental example

[0173] The wiring material has a circular cross section and a width of 300 μm. The wiring material was attached to the solar cell. The adhesive force was measured and is shown in Figure 16.

[0174] In FIG. 16, the horizontal axis represents the distance and the vertical axis represents the adhesive force. The first section I begins when the experimental device starts to pull the wiring. The first section is the section before the wire is fully tensioned, and the second section is the section where the experimental equipment actually tensions the wire. The third section III indicates the section after the wire is separated from the pad. Therefore, the actual adhesive strength can be confirmed through the second section II.

[0175] The first section I is a section with a small distance, and no force is actually applied to the wiring material in the first section I. I can't.

[0176] In the second section II, the experimental equipment pulls the wiring material, so as the distance increases, The stress applied to the wiring also increases in proportion to the distance. More specifically, the adhesive force increases in the second section II. , peaking at 2.058N and then dropping sharply.

[0177] The third section III is a section after the highest point of adhesion, where the wiring material is separated from the first pad. Therefore, the stress applied to the wiring material is rapidly reduced.

[0178] In this example, the adhesive strength of the wiring material was 2.058 N, which is an excellent value. It can be seen that

[0179] The above-described features, structures, effects, etc. are included in at least one embodiment of the present invention, The present invention is not necessarily limited to only one embodiment. The structure, effect, etc. of the embodiment may be understood by a person having ordinary skill in the art. The embodiments can be combined or modified. All such adaptations and modifications are to be construed as falling within the scope of the present invention.

Claims

1. a plurality of solar cells each including a semiconductor substrate having a photoelectric conversion unit, and a first electrode and a second electrode connected to the photoelectric conversion unit; a plurality of wiring members connecting adjacent solar cells of the plurality of solar cells, the plurality of wiring members connecting the first electrode of one solar cell among the adjacent solar cells to the second electrode of another solar cell adjacent thereto; In each of the plurality of solar cells, each of the first electrode and the second electrode includes a plurality of finger electrodes formed in a first direction and parallel to each other, and a plurality of bus bar electrodes formed in a second direction intersecting the first direction; each of the bus bar electrodes includes a line portion and a plurality of pad portions formed on the line portion, the plurality of pad portions being spaced apart from one another in the second direction, and the line portion connecting the plurality of pad portions in the second direction; an edge region (portion) where the finger electrodes are not formed is defined between an outermost pad portion of the plurality of pad portions and an edge of the semiconductor substrate adjacent to the outermost pad portion; each of the pad portions has a width in the second direction that is greater than a width of the plurality of finger electrodes; the plurality of pad portions include a plurality of first pad portions and a plurality of second pad portions having different widths in the first direction and different lengths in the second direction; the width of the wiring material is 250 μm to 500 μm, and the edge distance from the first pad portion to the adjacent edge of the semiconductor substrate is 2.37 mm to 21.94 mm; The solar cell panel, wherein the first pad portion is arranged inward from an outermost finger electrode among the plurality of finger electrodes.

2. The solar cell panel according to claim 1 , wherein the plurality of wiring members include six or more wiring members arranged on one surface of the solar cell, each of the wiring members being connected to the bus bar electrode.

3. The solar cell panel according to claim 2 , wherein each of the plurality of pad portions has a length in the second direction that is greater than a width of the plurality of finger electrodes.

4. 2. The solar cell panel according to claim 1, wherein each of the plurality of busbar electrodes has a distance between its two ends in the second direction that is shorter than a distance between outermost finger electrodes of the plurality of finger electrodes located at both ends of the photoelectric conversion unit in the second direction.

5. 2. The solar panel according to claim 1, wherein the edge distance is defined as a distance between one end of the busbar electrode and an adjacent end of the solar cell in the second direction, or a distance between another end of the busbar electrode and an adjacent end of the solar cell in the second direction.

6. When the width of the wiring material is 250 μm or more and less than 300 μm, the edge distance is 2.37 mm to 9.78 mm; When the width of the wiring material is 300 μm or more and less than 350 μm, the edge distance is 3.99 mm to 12.94 mm; When the width of the wiring material is 350 μm or more and less than 400 μm, the edge distance is 5.06 mm to 15.98 mm; When the width of the wiring material is 400 μm or more and less than 450 μm, the edge distance is 5.69 mm to 18.96 mm; 6. The solar cell panel according to claim 5, wherein the edge distance is 5.94 mm to 21.94 mm when the width of the wiring material is 450 μm to 500 μm.

7. A solar cell panel as described in any one of claims 1 to 6, including a configuration in which the width in the first direction and the length in the second direction of the plurality of first pad portions are wider than the width in the first direction and longer than the length in the second direction of the plurality of second pad portions, and the plurality of first pad portions are arranged at the ends of the line portion in the second direction.

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