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1. WO2020109969 - SOLAR CELL MODULE

Note: Text based on automatic Optical Character Recognition processes. Please use the PDF version for legal matters

[ EN ]

SOLAR CELL MODULE

TECHNICAL FIELD

The present application relates to the technical field of photovoltaic cells, in particular to a solar cell module.

BACKGROUND

With the gradual increase of environmental problems, the development and application of clean energies are becoming more and more urgent. Solar energy has received more and more attention as a clean energy source. A solar cell is a device that uses solar energy to generate electricity.

Currently, the common solar cells include a battery body that is encapsulated in an encapsulation cover and an encapsulation back sheet. Light is incident on the light-facing surface of the battery body through the encapsulation cover, and the battery body converts the light energy in the light into electrical energy.

At present, the power generation efficiency of solar cells is low and the safety thereof is sometimes poor. How to improve the power generation efficiency of solar cells while ensuring safety has become one of the technical problems to be solved in the field.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a solar cell module which can achieve high power generation efficiency while satisfying safety.

Specifically, the present invention provides a solar cell module comprising a light transmissive element, a front encapsulation layer, a plurality of solar cells spaced apart from each other, a post encapsulation layer, and a back sheet disposed in a thickness direction of the solar cell module in turn, wherein the plurality of solar cells spaced apart from each other form an array, the array comprising a plurality of mutually parallel solar cell strings in the same plane perpendicular to the thickness direction, each of the solar cell strings being composed of a plurality of solar cells connected in series, and a string gap is formed between each two adjacent solar cell strings, wherein the solar cell module further includes a light redirecting film disposed on a surface of the back sheet inside the solar cell module, and an orthogonal projection of the light redirecting film on the back sheet substantially coincides with an orthogonal projection of the string gap on the back sheet, wherein the light redirecting film includes a concave-convex reflective structure, and the concave-convex reflective structure includes an array of abutting triangular prisms, and wherein an angle between an orthographic projection of an orientation direction of the array of abutting triangular prisms on the back sheet and an orthographic projection of the solar cell strings on the back sheet is in a range of 45-80 degrees, and a vertical distance between a plane where apexes of the concave-convex reflective structure are located and a plane where the solar cells are located is in a range of 200 - 600 pm.

According to certain preferable embodiments of the present invention, the angle between an orthographic projection of an orientation direction of the array of abutting triangular prisms on the back sheet and an orthographic projection of the solar cell strings on the back sheet is in a range of 60-80 degrees.

According to certain preferable embodiments of the present invention, the vertical distance between a plane where apexes of the concave-convex reflective structure are located and a plane where the solar cells are located is in a range of 400 - 550 pm.

According to certain preferable embodiments of the present invention, the orientation direction of the array of abutting triangular prisms is non-linearly oriented.

According to certain preferable embodiments of the present invention, the orientation direction of the array of abutting triangular prisms is linearly oriented.

According to certain preferable embodiments of the present invention, the array of abutting triangular prisms is an array of parallel triangular prisms wherein one quadrilateral plane of each triangular prism is in the same plane perpendicular to the thickness direction of the solar cell module.

According to certain preferable embodiments of the present invention, the orientation direction of the array of abutting triangular prisms is a direction perpendicular to a cross section having a smallest area of each triangular prism in the array of abutting triangular prisms.

According to certain preferable embodiments of the present invention, a cell gap is formed between each two adjacent solar cells in each of the solar cell strings.

According to certain preferable embodiments of the present invention, an apex angle of each triangular prism in the array of abutting triangular prisms toward the solar cells is in a range of 100 degrees - 140 degrees.

According to certain preferable embodiments of the present invention, an apex angle of each triangular prism in the array of abutting triangular prisms toward the solar cells is in a range of 110 degrees - 130 degrees.

According to certain preferable embodiments of the present invention, a vertical distance from a highest point to a lowest point of the concave-convex reflective structure is between 1 and 25 pm.

According to certain preferable embodiments of the present invention, the light redirecting film is fixed to a surface of the back sheet inside the solar cell module by an adhesive layer.

According to certain preferable embodiments of the present invention, the adhesive layer is an ethylene- vinyl acetate copolymer adhesive layer, a polyolefin resin adhesive layer, a polypropylene oxide adhesive layer, a polyvinyl butyral adhesive layer, a

tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride copolymer adhesive layer, an ethyl ene-tetrafluoroethylene copolymer adhesive layer, a polyvinylidene fluoride adhesive layer, a polyurethane adhesive layer, a polymethyl methacrylate adhesive layer, a polyimide adhesive layer, an acrylic adhesive layer or an acrylate adhesive layer.

According to certain preferable embodiments of the present invention, the adhesive layer has a thickness between 10 pm and 100 pm.

According to certain preferable embodiments of the present invention, the light redirecting film further comprises a base layer, and the concave-convex reflective structure is disposed on the base layer.

According to certain preferable embodiments of the present invention, the base layer is a cellulose acetate butyrate layer, a cellulose acetate propionate layer, a cellulose triacetate layer, a poly(meth)acrylate layer, a polyethylene terephthalate layer, a polyethylene naphthalate layer, a polyethersulfone layer, a polyurethane layer, a polycarbonate layer, a polyvinyl chloride layer, a syndiotactic polystyrene layer, a cyclic olefin copolymer layer or a silicone layer.

According to certain preferable embodiments of the present invention, the base layer has a thickness between 10 pm and 100 pm.

According to certain preferable embodiments of the present invention, the light redirecting film further comprises a light reflecting layer, wherein the light reflecting layer covers the concave-convex reflective structure and conforms to the concave-convex reflective structure.

According to certain preferable embodiments of the present invention, the light reflecting layer is a metal layer.

According to certain preferable embodiments of the present invention, the light reflecting layer has a thickness between 30 nm and 100 nm.

According to certain preferable embodiments of the present invention, the light redirecting film has a total thickness between 20 pm and 150 pm.

The solar cell module according to the present invention has the advantages of:

1. By selecting a specific distance from the light redirecting film from the solar cells, the power generation efficiency of the solar cell module is improved by utilizing the reflection effect of the light redirecting film while sufficiently reducing the internal resistance of the solar cell module to improve safety;

2. By selecting a specific angle between an orientation direction of the array of abutting triangular prisms and an orthographic projection of the solar cell strings on the back sheet, the loss of light is reduced, thereby improving the power generation efficiency of the solar cell module.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 shows a cross-sectional view of a solar cell module having a light redirecting film; Fig. 2 shows a cross-sectional view of a solar cell module in accordance with an embodiment of the present invention;

Fig. 3 shows a top view of an array formed of a plurality of solar cells spaced apart from each other in accordance with an embodiment of the present invention;

Fig. 4 shows a perspective view of a concave-convex reflective structure included in a light redirecting film according to an embodiment of the present invention;

Fig. 5 shows a top view of one of the triangular prisms in an array of abutting triangular prisms in accordance with three different embodiments of the present invention; and

Fig. 6 shows a cross-sectional view of a light redirecting film in a direction perpendicular to an orientation direction of the array of abutting triangular prisms, in accordance with an embodiment of the present invention.

Reference markers:

1 : a solar cell module; 2: a light transmissive element; 3 : a front encapsulation layer; 4: a solar cell; 5: a post encapsulation layer; 6: a back sheet; 7: an array of solar cells; 8: a solar cell string; 9: a string gap; 10: a cell gap; 11 : a light redirecting film; 12: a surface of the back sheet inside the solar cell module; 13 : a concave-convex reflective structure; 14: an array of abutting triangular prisms; 15: a triangular prism; 16: a plane perpendicular to the thickness direction of the solar cell module; 17: an adhesive layer; 18: a base layer; 19: a light reflecting layer

DETAILED DESCRIPTION OF THE PRESENT INVENTION

The present invention will be further described in detail below in conjunction with the drawings and specific embodiments. It will be appreciated that other embodiments may be practiced without departing from the scope or spirit of the present invention. Therefore, the following detailed description is non-limiting.

In order to improve the power generation efficiency of a solar cell module, a light redirecting film may be provided inside the solar cell module. When power is generated by the solar cell module, a light may be irradiated onto an optical structure of the light redirecting film after passing through a light transmissive element. The optical structure of the light redirecting film can reflect the incident light and change the direction thereof. Since the light is incident from top to bottom, the light redirecting film reflects the light upward toward the light transmissive element. When the light reflected by the light redirecting film enters the light transmissive element and propagates into the interface between the light transmissive element and air, the light is reflected and the direction of light propagation changes again, and finally the light-facing surfaces of the solar cells are illuminated by the light. Since the solar cells use the light to generate electricity, the power generation efficiency is improved. The light redirecting film is usually disposed on the back surfaces of the solar cells or on a surface of the back sheet inside the solar cell module.

When the light redirecting film is disposed on a surface of the back sheet inside the solar cell module, during the process of reflecting the light back to the light-facing surfaces of the solar cells through the light redirecting film, the light which is irradiated to the edge of the light redirecting film (that is, the portion close to the solar cells) may be reflected by the back surfaces of the solar cells, and thus may not reach the light-facing surfaces of the solar cells through the gap between the solar cells, thereby causing light loss. Fig. 1 shows a cross-sectional view of a solar cell module having a light redirecting film. As shown in Fig. 1, a solar cell module 1 comprises a light transmissive element 2, a front encapsulation layer 3, a plurality of solar cells 4 spaced apart from each other, a post encapsulation layer 5, and a back sheet 6 disposed in a thickness direction T of the solar cell module 1 in turn, wherein the plurality of solar cells 4 spaced apart from each other form an array, and the solar cell module 1 comprises further comprises a light redirecting film 11. The light which is irradiated onto the light redirecting film 11 is reflected, and finally irradiated on the light-facing surfaces of the solar cells 4 along a direction A. However, the light which is irradiated to the edge of the light redirecting film is reflected by the back surfaces of the solar cells along a direction B, and cannot reach the light-facing surfaces of the solar cells through the gap between the solar cells, thereby causing light loss.

Furthermore, the light redirecting film is usually disposed on the back surfaces of the solar cells or on a surface of the back sheet inside the solar cell module by an adhesive layer. We have found that, in some cases, the preparation of the solar cell module by high temperature lamination may result in the relative positional drift of the light directing film (that is, the positional shift of the light directing film), which may reduce the power generation efficiency of the solar cell module.

Further, the closer the light redirecting film is to the solar cells, the better the effect of achieving light reflection, and the higher the power generation efficiency. Since the back surface of the solar cells are usually covered with a metal layer (for example, an aluminum layer) and the microstructures on the surface of the light redirecting film are usually covered with a metal reflective layer, if the distance between the light redirecting film and the solar cells is smaller, it may result in electrical conduction between adjacent solar cells and the risk of damage to the solar cell module.

In order to solve the above technical problems, the present invention provides a solar cell module.

Fig. 2 shows a cross-sectional view of a solar cell module in accordance with an embodiment of the present invention. As shown in Fig. 2, the present invention provides a solar cell module 1 comprising a light transmissive element 2, a front encapsulation layer 3, a plurality of solar cells 4 spaced apart from each other, a post encapsulation layer 5, and a back sheet 6 disposed in a thickness direction T of the solar cell module 1 in turn, wherein the plurality of solar cells 4 spaced apart from each other form an array. Fig. 3 shows a top view of an array 7 formed of a plurality of solar cells 4 spaced apart from each other in accordance with an embodiment of the present invention. The array 7 comprises a plurality of mutually parallel solar cell strings 8 in the same plane perpendicular to the thickness direction T (for example, a solar cell string 8 formed of solar cells 4a, 4b, and 4c in the longitudinal direction of the array 7, and a solar cell string 8 formed of solar cells 4d, 4e, and 4f in the longitudinal direction of the array 7). Each of the solar cell strings 8 is composed of a plurality of solar cells 4 (for example, solar cells 4a, 4b, 4c, 4d, 4e, and 4f) connected in series. A string gap 9 is formed between each two adjacent solar cell strings 8, and a cell gap 10 is formed between each two adjacent solar cells 4 in each of the solar cell

strings 8. It should be noted that when the solar cell sheets are in a stacked structure, there may be no sheet gap 10 between two adjacent solar cells 4 in each of the solar cell strings 8.

As shown in Fig. 2, the solar cell module 1 further includes a light redirecting film 11 disposed on a surface 12 of the back sheet 6 inside the solar cell module 1. An orthogonal projection of the light redirecting film 11 on the back sheet 6 substantially coincides with an orthogonal projection of the string gap 9 and/or the cell gap 10 on the back sheet 6. The orthogonal projection of the light redirecting film 11 on the back sheet 6 is preferably slightly wider than the string gap 9 or the cell gap 10. The width of the light redirecting film is greater than the width of the string gap 9 or the width of the cell gap 10 by 0.5 to 5 mm, preferably 0.5 to 4 mm, preferably 0.5 to 3 mm, preferably 0.5 to 2 mm, most preferably 0.5 to 1 mm. Since the relative positional shift of the light redirecting film may occur during the high temperature lamination preparation of the solar cell module, the width of the light redirecting film is controlled to be larger than the width of the string gap 9 or the width of the cell gap 10 to ensure the string gap and/or the cell gap can be fully utilized to transmit the reflected light, thereby ensuring a higher power gain of the solar cell module.

The light redirecting film 11 includes a concave-convex reflective structure 13. Fig. 4 shows a perspective view of a concave-convex reflective structure 13 included in a light redirecting film 11 according to an embodiment of the present invention. As shown in Fig. 4, the concave-convex reflective structure 13 includes an array 14 of abutting triangular prisms wherein one quadrilateral plane of each triangular prism 15 is in the same plane 16 perpendicular to the thickness direction of the solar cell module 1.

According to certain preferable embodiments of the present invention, the term“an array of abutting triangular prisms” refers to an array comprising a plurality of triangular prisms arranged side by side. According to certain preferable embodiments of the present invention, each triangular prism in the array of abutting triangular prisms is a triangular prism having an apex angle being 120 degrees toward the solar cells and two base angles being 30 degrees respectively. Optionally, the sharp peak of at least one triangular prism in the array of abutting triangular prisms toward the solar cells may be replaced by a round peak. Preferably, the round peak of the at least one triangular prism in the array of abutting triangular prisms has a radius of curvature of from 0.2 micron to 5 microns.

As shown in Fig. 4, the orientation direction D of the array 14 of abutting triangular prisms is a direction perpendicular to a cross section having a smallest area of each triangular prism 15 in the array 14 of abutting triangular prisms. As shown in Fig. 3, the orthographic projection of an orientation direction D of the array 14 of abutting triangular prisms on the back sheet 6 and an orthographic projection of the solar cell strings 8 on the back sheet 6 form an angle a. As mentioned above, during the process of reflecting the light back to the light-facing surfaces of the solar cells through the light redirecting film, the light which is irradiated to the edge of the light redirecting film (that is, the portion close to the solar cells) may be reflected by the back surfaces of the solar cells, and thus may not reach the light-facing surfaces of the solar cells through the gap between the solar cells, thereby causing light loss. In order to reduce the light loss described above to increase the power of the module, the angle a between an orthographic projection of an orientation direction D of the array 14 of abutting triangular prisms on the back sheet 6 and an orthographic projection of the solar cell strings 8 on the back sheet 6 is in a range of 45-80 degrees. According to the technical solution of the present invention, when the angle a is in the range of 45-80 degrees, compared with the solar cell module without a light redirecting film, the power gain of the solar module of the present invention measured according to IEC61215 under standard test conditions (AMI .5, 25°C, 1000W/m2) can be more than 2.45%. However, when the angle a is 85 degree, compared with the solar cell module without a light redirecting film, the power gain of the solar module of the present invention measured according to IEC61215 under standard test conditions (AMI .5, 25°C, 1000W/m2) is only 1.93%, which shows poor effect. Preferably, the angle a between an orthographic projection of an orientation direction D of the array 14 of abutting triangular prisms on the back sheet 6 and an orthographic projection of the solar cell strings 8 on the back sheet 6 is in a range of 60-80 degrees, and the selection of the angle a within this range enables the maximum utilization of reflected light for maximum power gain of the solar module. According to the technical solution of the present invention, when the angle a is in the range of 60-80 degrees, compared with the solar cell module without a light redirecting film, the power gain of the solar module of the present invention measured according to IEC61215 under standard test conditions (AMI .5, 25°C, 1000W/m2) can be 3.00% or more.

Additionally, although the closer the light redirecting film is to the solar cells, the better the effect of achieving light reflection, in view of the problem of electrical conduction between adjacent solar cells and the risk of damage to the solar cell module if the distance between the light redirecting film and the solar cells is smaller, as shown in Fig. 2, a vertical distance d between a plane where the apexes of the concave-convex reflective structure 13 are located and a plane where the solar cells 4 are located is in a range of 200 - 600 pm. Preferably, a vertical distance d between a plane where the apexes of the concave-convex reflective structure 13 are located and a plane where the solar cells 4 are located is in a range of 400 - 550 pm. When the vertical distance d between a plane where the apexes of the concave-convex reflective structure 13 are located and a plane where the solar cells 4 are located is less than 200 pm, it may result in electrical conduction between adjacent solar cells and the risk of damage to the solar cell module.

Preferably, when the angle a between an orthographic projection of an orientation direction D of the array 14 of abutting triangular prisms on the back sheet 6 and an orthographic projection of the solar cell strings 8 on the back sheet 6 is in a range of 60-80 degrees, and a vertical distance d between a plane where the apexes of the concave-convex reflective structure 13 are located and a plane where the solar cells 4 are located is in a range of 200 - 600 pm, it is possible to achieve the maximum light utilization efficiency and the optimum light reflection effect while avoiding electrical conduction between adjacent solar cells so as to improve safety, thereby achieving good power gain of solar cell module.

Preferably, as shown in Fig. 4, an apex angle b of each triangular prism in the array 14 of abutting triangular prisms toward the solar cells 4 is in a range of 100 degrees - 140 degrees. More preferably, an apex angle b of each triangular prism in the array 14 of abutting triangular prisms toward the solar cells 4 is in a range of 110 degrees - 130 degrees.

Preferably, in or to further optimize the reflective effect, a vertical distance from a highest point to a lowest point of the concave-convex reflective structure 13 is between 1 and 25 pm.

In the perspective view of a concave-convex reflective structure 13 shown in Fig. 4 above, the three sides of each of the triangular prisms 15 are linear (that is, straight). However, the present invention is not limited thereto. Optionally, the orientation direction of the array of abutting triangular prisms is non-linearly oriented (that is, curved). Fig. 5 shows a top view of one of the triangular prisms in an array of abutting triangular prisms in accordance with three different embodiments of the present invention. In the triangular prisms a, b, and c shown in Fig. 5, the intermediate lines are respectively the comer lines of the triangular prisms protruding toward the solar cells. As shown in Fig. 5, in the triangular prism a, the apex line extends in a straight line and the remaining two sides extend in a curved shape; in the triangular prism b, the apex angle line and the remaining two sides extend in a regular wave shape. In the triangular prism c, the apex angle and the remaining two sides extend irregularly in a wave shape. In the case where the orientation direction of the array of abutting triangular prisms is non-linearly

oriented, the orientation direction D of the array of abutting triangular prisms is the extending direction of the array of abutting triangular prisms.

The specific shape of the solar cells is not particularly limited, and may be specifically selected according to actual needs from the shapes generally employed in the field. Preferably, each of the solar cells has a square shape or a rectangular shape.

In the present invention, there is no special provision on how to place the light redirecting film on the back sheet. For example, as a specific embodiment, each of the light redirecting films is fixed to a surface of the back sheet inside the solar cell module by an adhesive or a tape.

In the present invention, the specific structure of the light redirecting film is not particularly limited. For ease of manufacture, preferably, each of the light redirecting films further includes a base layer, and the concave-convex reflective structure is disposed on the base layer.

In the present invention, the light redirecting film may further include an adhesive layer, and the adhesive layer and the concave-convex reflective structure are respectively disposed on both sides of the base layer in the thickness direction thereof. The light redirecting film may be bonded to the surface of the back sheet inside the solar cell module by using an adhesive layer. The adhesive can be a pressure sensitive adhesive or a hot melt adhesive.

Fig. 6 shows a cross-sectional view of a light redirecting film in a direction perpendicular to an orientation direction of the array of abutting triangular prisms, in accordance with an embodiment of the present invention. As shown in Fig. 6, the light redirecting film 11 includes an adhesive layer 17, a base layer 18, and a concave-convex reflective structure 13 which are sequentially disposed in the thickness direction thereof. The light redirecting film 11 is fixed to the surface 12 of the back sheet 6 inside the solar cell module 1 by the adhesive layer 17. The specific type of the adhesive for fixing the light redirecting film 11 to the back sheet 6 is not particularly limited, and an adhesive which is generally employed in the field may be employed. Preferably, the adhesive layer 17 is an ethylene-vinyl acetate copolymer adhesive layer, a polyolefin resin adhesive layer, a polypropylene oxide adhesive layer, a polyvinyl butyral adhesive layer, a tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride copolymer adhesive layer, an ethyl ene-tetrafluoroethylene copolymer adhesive layer, a polyvinylidene fluoride adhesive layer, a polyurethane adhesive layer, a polymethyl methacrylate adhesive layer, a polyimide adhesive layer, an acrylic adhesive layer or an acrylate adhesive layer. Specifically, the adhesive layer according to the present invention is formed by coating an ethylene-vinyl acetate copolymer adhesive disclosed in CN 201710559405.2. Preferably, the adhesive layer 17

has a thickness of between 10 and 100 mih, preferably between 10 and 50 pm. By using the ethylene-vinyl acetate copolymer adhesive as described above and controlling the thickness of the adhesive layer to be between 10 and 50 pm, the relative positional drift of the light directing film, which may reduce the power generation efficiency of the solar cell module, can be effectively avoided. Specifically, when the thickness of the adhesive layer is controlled to be between 10 and 50 pm, the relative positional shift of the light redirecting film is less than 0.5 mm; when the thickness of the adhesive layer is controlled to be greater than 50 to 100 pm, the relative positional shift of the light redirecting film is between 0.5 mm and 1 mm; and when the thickness of the adhesive layer is controlled to be more than 100 pm, it may cause whitening at the position of the light redirecting film of the solar cell module, the appearance of the solar cell module is poor, and power gain of the module is reduced.

There is no particular limitation on the material constituting the base layer 18. Preferably, the base layer 18 is a cellulose acetate butyrate layer, a cellulose acetate propionate layer, a cellulose triacetate layer, a poly(meth)acrylate layer, a polyethylene terephthalate layer, a polyethylene naphthalate layer, a polyethersulfone layer, a polyurethane layer, a polycarbonate layer, a polyvinyl chloride layer, a syndiotactic polystyrene layer, a cyclic olefin copolymer layer or a silicone layer. Preferably, the base layer 18 has a thickness of between 10 and 100 pm.

As shown in Fig. 6, the light redirecting film further comprises a light reflecting layer 19, wherein the light reflecting layer 19 covers the concave-convex reflective structure 13 and conforms to the concave-convex reflective structure 13.

The material of the light reflecting layer may be a metal material. A metal material may be deposited on a triangular prism by sputtering to obtain the light reflecting layer.

Preferably, the light reflecting layer is a metal layer. In order to obtain a higher reflectance, preferably, the material of the light reflecting layer includes one or more of highly reflective metals such as gold, silver, aluminum, platinum, titanium or the like, or an alloy thereof.

For ease of manufacture, preferably, the reflective layer has a thickness between 30 and 100 nm.

Preferably, the light redirecting film has a total thickness between 20 pm and 150 pm.

In the present invention, the specific materials of the front encapsulation layer and the post encapsulation layer are not particularly limited. For example, the front encapsulation layer and the post encapsulation layer can be made using an ethylene-vinyl acetate copolymer (that is, EVA) material. The front encapsulation layer and the post encapsulation layer may be formed of the same material or may be formed of different materials.

For an array including solar cells having a thickness of 0.2 mm, it may be packaged with a front encapsulation layer having a thickness of 0.5 mm and a post encapsulation layer having a thickness of 0.5 mm.

The light transmissive element 2 can be made of a high-transmission embossed glass, and the back sheet 6 can be made of a black back sheet (for example, a black back sheet manufactured by Jinko Energy Co., Ltd.). For an array comprising solar cells 4 having a thickness of 0.2 mm, the thickness of the light transmissive element 2 can be 3.2 mm. The back sheet 6 can also be a glass, which can have a thickness of 2.5 mm.

As a preferred embodiment, the solar cell module may include 60 pieces of solar cells. The size of the solar cell sheet can be 156 mm x 156 mm. In this embodiment, the solar cell module includes 6 battery strings, each of which includes 10 solar cell sheets. In the present invention, there is no special requirement for the size of the cell gap and the size of the string gap. For example, as a preferred embodiment, the width of the string gap is the same as the width of the cell gap, thereby facilitating the assembling. Specifically, the width of the string gap may be between 1 mm and 20 mm. Additionally, the width of the cell gap can be between 0 mm and 20 mm (in the case where the solar cell sheets are in a stacked structure, the width of the cell gap is 0 mm). For a half-piece solar cell module, the solar cell size can be 156 mm x 78 mm, and the overall module includes 120 half-chip solar cells. In this embodiment, the solar cell module includes 6 solar cell strings, each of which includes 20 solar cell sheets. The width of the string gap can be between 1 mm and 12 mm. Additionally, the width of the cell gap may be between 0 mm and 12 mm (in the case where the solar cell sheets are in a stacked structure, the width of the cell gap is 0 mm).

Obviously, various modifications and variations may be made to this disclosure by the person skilled in the art without deviating from the scope of this disclosure. Thus, if these modifications and variations of this disclosure are within the scope of the claims of this invention and equivalent techniques thereof, this disclosure also intends to encompass these modifications and variations.