Solar cell module and photovoltaic system

Abstract

The utility model relates to the technical field of solar cells, and particularly discloses a solar cell module and a photovoltaic system, comprising a cell string, the cell string comprises a plurality of cells which are connected in series and arranged along a first direction, a bus bar, a backlight surface arranged on at least one cell, an insulating strip, and a plurality of solar cells arranged between the bus bar and the cells, the bus bar and the insulating strip extend along a first direction, the bus bar and the insulating strip extend along a second direction, the first direction and the second direction are crossed, the insulating strip comprises a base material and a bonding layer arranged on one side or two sides of the thickness direction of the base material, the anti-breakdown voltage of the insulating strip is greater than or equal to 100V, and the reflectivity of the insulating strip is greater than or equal to 65% within the wavelength range of 800nm-1100nm. According to the utility model, the effective light-receiving area of the battery assembly can be increased, the conversion efficiency of the assembly can be improved, the observed area of the bus bar from one side of the light-receiving surface is smaller, even the bus bar can be completely hidden and is more beautiful, and meanwhile, the long-term reliability of the battery assembly can be improved.

Description

Technical Field

[0001] This utility model relates to the field of solar cell technology, and in particular to a solar cell module and photovoltaic system. Background Technology

[0002] In existing back-contact battery modules, the series busbars between adjacent battery strings are usually installed at the edge of the module, while the parallel busbars between adjacent battery strings are usually installed in the reserved gap area between the two battery strings. This requires a certain amount of space to be reserved at the edge of the battery module to place the series busbars, and a certain amount of space to be reserved between the two parallel battery strings to place the parallel busbars. On the one hand, this reduces the effective light-receiving area of ​​the battery module and affects the module conversion efficiency; on the other hand, it affects the aesthetics of the battery module. Utility Model Content

[0003] The purpose of this invention is to provide a solar cell module and photovoltaic system in response to the existing technological status quo.

[0004] This invention can increase the effective light-receiving area of ​​the battery module, improve the module conversion efficiency, reduce the area of ​​the busbar that is observed from the light-receiving side, and can even be completely hidden, making it more aesthetically pleasing. At the same time, it can improve the long-term reliability of the battery module.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] On the one hand, this utility model provides a solar cell module, comprising:

[0007] A battery string, comprising multiple battery cells connected in series and arranged along a first direction.

[0008] A busbar is disposed on the back surface of at least one of the solar cells.

[0009] An insulating strip is disposed between the busbar and the battery cell.

[0010] Both the busbar and the insulating strip extend along the second direction, and the first direction intersects with the second direction.

[0011] The insulating strip includes a substrate and an adhesive layer disposed on one or both sides of the substrate in the thickness direction. The insulating strip has a breakdown voltage ≥100V and a reflectivity ≥65% in the wavelength range of 800nm ​​to 1100nm.

[0012] In some embodiments, the thickness of the adhesive layer is greater than the thickness of the substrate, and the total thickness of the insulating strip is at least 2.5 times the thickness of the substrate.

[0013] In some embodiments, the adhesive layer is any one of an acrylic layer, a silicone layer, a POE layer, an EVA layer, and a PVB layer.

[0014] In some embodiments, the substrate includes an insulating base layer and a reflective layer disposed on at least one side of the insulating base layer in the thickness direction.

[0015] In some embodiments, the insulating base layer is any one of a PET layer, a PI layer, a POE layer, an EVA layer, and a PVB layer.

[0016] In some embodiments, the insulating base layer is a PET layer or a PI layer, and the adhesive layer includes a first EVA layer and a second EVA layer respectively disposed on both sides of the substrate thickness direction.

[0017] In some embodiments, the thermal shrinkage rate of the substrate along the first direction is ≤10%, and the thermal shrinkage rate of the substrate along the second direction is ≤10%.

[0018] In some embodiments, the battery string includes a first battery string and a second battery string arranged in a second direction and connected in series. The first battery string and the second battery string each have a first battery cell and a second battery cell arranged in a first direction. The first battery cell is located at the end of the battery string in which it is located. The same busbar and the same insulating strip extend from the second battery cell in the first battery string to the second battery cell in the second battery string. The busbar is located at the end of the second battery cell near the first battery cell. The first battery cell and the busbar are electrically connected by a first solder strip.

[0019] In some embodiments, the battery string includes a third battery string and a fourth battery string arranged in parallel along a first direction. Each battery string includes battery cells connected in series. Each battery cell includes a third battery cell and a fourth battery cell arranged along the first direction. The fourth battery cell is located at the end of the battery string in which it is located, and the third battery string and the fourth battery cell in the fourth battery string are arranged adjacent to each other in the first direction. The busbar is located at the edge of the third battery cell in the third battery string. The battery assembly also includes a second solder strip, which electrically connects the busbar, the fourth battery cell in the third battery string, and the fourth battery cell in the fourth battery string.

[0020] On the other hand, this utility model provides a photovoltaic system including the aforementioned battery components.

[0021] The beneficial effects of this utility model are as follows:

[0022] In this invention, the busbar is located on the back surface of the solar cell, and the busbar is separated from the solar cell by an insulating strip. On one hand, the edge of the battery module no longer needs to reserve space for the busbar, allowing for more space to install the solar cells, resulting in a larger effective light-receiving area and higher conversion efficiency. On the other hand, when viewed from the light-receiving surface (or "front") of the solar cell, the insulating strip can obscure the busbar, improving the overall aesthetics of the battery module. Furthermore, the insulating strip consists of a substrate and an adhesive layer, and its breakdown voltage is ≥100V. It can provide stable insulation performance, and the reflectivity of the insulating strip is ≥65% in the wavelength range of 800nm ​​to 1100nm. When light in the infrared band passes through the cell, the insulating strip can reflect this part of the light onto the cell, thereby improving the utilization rate of light and avoiding the impact of the bifaciality of the battery module on the busbar built into the cell, further improving the module conversion efficiency. At the same time, after lamination, the adhesive layer can form a durable and firm connection between the insulating strip and the busbar, the cell, and the encapsulation material (EVA film) of the battery module, thereby improving the long-term reliability of the battery module. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of a solar cell module according to Embodiment 1 of this utility model.

[0024] Figure 2 This is a schematic diagram of one embodiment of the insulating strip of this utility model (Example 1).

[0025] Figure 3 This is a schematic diagram of another embodiment of the insulating strip of this utility model.

[0026] Figure 4 This is a schematic diagram of the structure of a solar cell module according to Embodiment 1 of this utility model.

[0027] Figure 5 This is a schematic diagram of the structure of a solar cell module according to Embodiment 2 of this utility model.

[0028] Figure 6 This is a schematic diagram of the structure of an insulating block used in a solar cell module according to Embodiment 3 of this utility model.

[0029] Figure 7 This is a schematic diagram of the structure of an insulating strip with through holes in a solar cell module according to Embodiment 3 of this utility model. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. Furthermore, it should be understood that the specific embodiments described herein are merely for explaining this application and are not intended to limit this application.

[0031] In the description of this application, the terms "first," "second," "third," "fourth," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first," "second," "third," "fourth," etc., may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0032] Example 1

[0033] See Figures 1 to 3 As shown, this embodiment provides a solar cell module, including:

[0034] The battery string comprises multiple battery cells 1 connected in series and arranged along a first direction.

[0035] Busbar 2 is disposed on the back surface of at least one of the battery cells 1.

[0036] Insulating strip 3 is disposed between the busbar 2 and the battery cell 1.

[0037] Both the busbar 2 and the insulating strip 3 extend along the second direction, and the first direction intersects with the second direction.

[0038] The insulating strip 3 includes a substrate 31 and an adhesive layer 32 disposed on one or both sides of the substrate 31 in the thickness direction. The insulation strip 3 has a breakdown voltage ≥100V and a reflectivity ≥65% in the wavelength range of 800nm ​​to 1100nm.

[0039] In this invention, the busbar 2 is disposed on the backlight surface of the battery cell 1, and the busbar 2 is separated from the battery cell 1 by an insulating strip 3. On the one hand, the edge of the battery assembly no longer needs to reserve space for the busbar 2, allowing for more space to install the battery cell 1, resulting in a larger effective light-receiving area and higher conversion efficiency. On the other hand, when viewed from the light-receiving surface (or "front") of the battery cell 1, the insulating strip 3 can shield the busbar 2, preventing it from being exposed, thus improving the overall aesthetics of the battery assembly. Furthermore, the insulating strip 3 is composed of a substrate 31 and an adhesive layer 32, wherein the insulating strip 3 has resistance to breakdown voltage. With a voltage rating of ≥100V, it can provide stable insulation performance. Furthermore, the insulation strip 3 has a reflectivity of ≥65% in the wavelength range of 800nm ​​to 1100nm. When light in the infrared band passes through the cell 1, the insulation strip 3 can reflect this part of the light back onto the cell 1, thereby improving the utilization rate of light and avoiding the impact of the busbar 2 being built into the cell 1 on the bifaciality of the battery module, further improving the module conversion efficiency. At the same time, after lamination, the adhesive layer 32 can form a durable and firm connection between the insulation strip 3 and the busbar 2, the cell 1, and the encapsulation material (EVA film) of the battery module, thereby improving the long-term reliability of the battery module.

[0040] It is understandable that in a battery string, the battery string may include two battery cells 1 connected in series, three battery cells 1 connected in series, or more battery cells 1. The specific number of battery cells 1 that need to be connected in series can be determined according to the actual use.

[0041] Optionally, adjacent cells 1 in the same battery string can be connected in series by means of soldering ribbon, conductive adhesive, etc.

[0042] Optionally, in the same battery string, adjacent battery cells 1 are arranged at intervals or have partial overlap (i.e., stacked cells).

[0043] In some embodiments, see Figures 2 to 3 As shown, the thickness of the adhesive layer 32 is greater than the thickness of the substrate 31, and the total thickness of the insulating strip 3 is at least 2.5 times the thickness of the substrate 31. On the one hand, this ensures that the adhesive layer 32 has high strength and long-lasting bonding performance. On the other hand, it enables the adhesive layer 32 to protect the substrate 31, ensuring that the insulating strip 3 always maintains good insulation and reflective performance during long-term use.

[0044] In some embodiments, the adhesive layer 32 is any one of an acrylic layer, a silicone layer, a POE layer, an EVA layer, and a PVB layer.

[0045] On the one hand, these materials have good bonding strength after lamination, which enables the insulating strip 3 to form a stable and firm connection with the busbar 2, the battery cell 1, and the encapsulation material (EVA film) of the battery module. On the other hand, these materials have a certain degree of flexibility and elasticity, which can tolerate and absorb the unevenness of the surface to which they are applied, and can protect the substrate 31.

[0046] In some embodiments, see Figures 2 to 3 As shown, the substrate 31 includes an insulating base layer 312 and a reflective layer 311 disposed on at least one side of the insulating base layer 312 in the thickness direction.

[0047] The insulating base layer 312 provides insulation performance, and the reflective layer 311 provides light reflection effect.

[0048] In some embodiments, the insulating base layer 312 is any one of a PET layer, a PI layer, a POE layer, an EVA layer, and a PVB layer.

[0049] In some embodiments, see Figures 2 to 3 As shown, the insulating base layer 312 is a PET layer or a PI layer, and the adhesive layer 32 includes a first EVA layer and a second EVA layer respectively disposed on both sides of the substrate 31 in the thickness direction.

[0050] Preferably, the insulating base layer 312 is a PET layer, and the adhesive layer 32 includes a first EVA layer and a second EVA layer respectively disposed on both sides of the substrate 31 in the thickness direction. PI layer is expensive, and using PET layer can effectively reduce material costs.

[0051] In some embodiments, the thermal shrinkage rate of the substrate 31 along the first direction is ≤10%, and the thermal shrinkage rate of the substrate 31 along the second direction is ≤10%. When the thermal shrinkage rate of the substrate 31 is too high, it is easy to cause mechanical stress, which may lead to problems such as microcracks and fragments in the battery cell 1. It may also change its position or shape, affecting the effect of electrical isolation.

[0052] In this embodiment, busbar 2 is an end busbar; for details, see [link to documentation]. Figure 4 As shown:

[0053] The battery string includes a first battery string 10A and a second battery string 10B arranged in a second direction and connected in series. The first battery string 10A and the second battery string 10B are each provided with a first battery piece 11 and a second battery piece 12 arranged in a first direction. The first battery piece 11 is located at the end of the battery string in which it is located. The same busbar 2 and the same insulating strip 3 extend from the second battery piece 12 in the first battery string 10A to the second battery piece 12 in the second battery string 10B. The busbar 2 is located at the end of the second battery piece 12 near the first battery piece 11. The first battery piece 11 and the busbar 2 are electrically connected by a first solder strip 41.

[0054] In this embodiment, the first battery cell 11 is located at the end of the battery string. For ease of explanation, in this embodiment, the end where the first battery cell 11 is located is referred to as the tail end of the battery string. That is, in the first direction, the first battery cell 11 is the last battery cell 1 of the battery string, and the second battery cell 12 is the second to last battery cell 1 of the battery string. It is easy to understand that the end where the first battery cell 11 is located can also be referred to as the head end of the battery string, which will not be elaborated here.

[0055] In one embodiment, adjacent battery cells 1 are connected by series welding ribbons 51. Specifically, the series welding ribbons 51 include a first series welding ribbon 511 and a second series welding ribbon 512. In a first direction, the first series welding ribbon 511 and the second series welding ribbon 512 are staggered. In a battery string, the Nth battery cell 1, the N+1th battery cell 1, and the N+2th battery cell 1 (N is a positive integer greater than 1) are arranged sequentially along the first direction. The positive electrode solder joint of the Nth battery cell 1 and the negative electrode solder joint of the N+1th battery cell 1 are connected in series by multiple first series welding ribbons 511, and the positive electrode solder joint of the N+1th battery cell 1 and the negative electrode solder joint of the N+2th battery cell 1 are connected in series by multiple second series welding ribbons 512.

[0056] Furthermore, the first solder strip 41 includes a first positive solder strip 411 and a first negative solder strip 412. The same first busbar 2 is electrically connected to the first positive solder strip 411 in one battery string and electrically connected to the first negative solder strip 412 in another battery string, so that adjacent battery strings are connected in series.

[0057] For example, the same series battery string group includes a first battery string 10A and a second battery string 10B. The first solder strip 41 includes a first positive solder strip 411 and a first negative solder strip 412. In the same series battery string group, the same first bus bar 2 extends from the second battery cell 12 in the first battery string 10A to the second battery cell 12 in the second battery string 10B. In the first battery string 10A, the first bus bar 2 is electrically connected to the first positive solder strip 411 on the first battery cell 11. In the second battery string 10B, the first bus bar 2 is electrically connected to the first negative solder strip 412 on the first battery cell 11.

[0058] Compared to placing the busbar 2 in the middle of the back of the battery cell 1, the busbar 2 of this invention is placed at the end of the second battery cell 12 near the first battery cell 11. The first welding strip 41 can fully adhere to and weld with the effective welding position of the first battery cell 11, avoiding insufficient welding between the first welding strip 41 and the first battery cell 11 due to the installation of the busbar 2, which would affect the current collection. At the same time, after the first welding strip 41 is welded to the first battery cell 11, it can be directly connected to the busbar 2 without the need to open the insulating strip 3 or replace it with intermittently placed insulating blocks. During assembly, the insulating strip 3 only needs to be placed as a whole at the end of the second battery cell 12 near the first battery cell 11, which effectively reduces the production precision requirements and production difficulty. It can avoid short circuits caused by positional displacement when opening the insulating strip or when the insulating block is laminated, and it can also avoid the impact of the opening of the insulating strip on the adhesion between the material layers, thus increasing the long-term reliability of the battery module.

[0059] Furthermore, when the busbar is placed on the outer edge of the last cell 1 of the battery string, that is, at the end of the first cell away from the second cell, the outer edge of the last cell of the battery string is close to the edge of the battery module. During lamination, the stress at this point is relatively large, which can easily lead to defects such as fragmentation. At the same time, the installation of the busbar will affect the welding between the first solder strip and the first cell. The first solder strip cannot be welded to the first cell at the position covered by the busbar, resulting in insufficient welding between the first solder strip and the first cell and poor current collection. This situation is particularly serious when the battery module is a back contact battery module without a main grid.

[0060] In contrast, the end busbar built-in structure of this utility model can be applied to battery modules with and without main grid back contact, making it more versatile. Furthermore, the end of the second battery cell 12 closest to the first battery cell 11 experiences less stress during lamination compared to the outer edge of the last battery cell 1 in the battery string, which can reduce the risk of fragmentation and cracking, and further improve the reliability of the battery module.

[0061] On the other hand, this embodiment provides a photovoltaic system including the aforementioned battery module.

[0062] Example 2

[0063] The difference between this embodiment and embodiment 1 is that in this embodiment, busbar 2 is an intermediate busbar. For details, please refer to... Figure 5 As shown:

[0064] The battery string includes a third battery string 20 and a fourth battery string 20 arranged in parallel along a first direction. Each battery string includes battery cells 1 connected in series. Each battery cell 1 includes a third battery cell 13 and a fourth battery cell 14 arranged along the first direction. The fourth battery cell 14 is located at the end of the battery string in which it is located, and the third battery string 20 and the fourth battery cell 14 in the fourth battery string 20 are arranged adjacent to each other in the first direction. The busbar 2 is located at the edge of the third battery cell 13 in the third battery string 20. The battery assembly also includes a second solder strip 42, which electrically connects the busbar 2, the fourth battery cell 14 in the third battery string 20, and the fourth battery cell 14 in the fourth battery string 20. The third battery cell 13 in the third battery string 20A is referred to as the third battery cell 13A, and the fourth battery cell 14 is referred to as the fourth battery cell 14A. The third battery cell 13 in the fourth battery string 20B is referred to as the third battery cell 13B, and the fourth battery cell 14 is referred to as the fourth battery cell 14B.

[0065] Furthermore, the second welding strip 42 includes a second positive welding strip and a second negative welding strip, and the fourth battery cell 14A, the fourth battery cell 14B and the busbar 2 are electrically connected through the second positive welding strip or the second negative welding strip.

[0066] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the structure and implementation principle of the back contact battery described above can be referred to the corresponding structure and implementation principle in the aforementioned Embodiment 1, and will not be repeated here.

[0067] Example 3

[0068] The difference between this embodiment and Embodiment 1 is that, see [link to Embodiment 1] Figure 6 and Figure 7 As shown, the busbar 2 and the insulating strip 3 are located in the middle of the back of the battery cell 1. The busbar 2 can be a middle busbar or an end busbar.

[0069] In one specific implementation, see Figure 7 As shown, the insulating strip 3 is a long strip structure with through holes 33. The same polarity solder strips on the battery cell 1 and the busbar 2 are exposed through the through holes 33 so that the busbar 2 can be electrically connected to the same polarity solder strips. The opposite polarity solder strips on the battery cell 1 and the busbar 2 are electrically isolated from the busbar 2 through the insulating strip 3.

[0070] In another specific implementation, see Figure 6 As shown, the insulating strip 3 is an insulating block arranged at intervals. The same polarity solder strips on the battery cell 1 and the busbar 2 are exposed through the gap between adjacent insulating blocks so that the busbar 2 can be electrically connected to the same polarity solder strips. The opposite polarity solder strips on the battery cell 1 and the busbar 2 are electrically isolated from the busbar 2 through the insulating blocks.

[0071] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the structure and implementation principle of the back contact battery described above can be referred to the corresponding structure and implementation principle in the aforementioned Embodiment 1, and will not be repeated here.

[0072] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Although the present utility model has been disclosed above with reference to a preferred embodiment, it is not intended to limit the present utility model. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present utility model. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present utility model without departing from the scope of the present utility model shall still fall within the scope of the present utility model.

Claims

1. A solar cell module, characterized in that, include: A battery string, comprising multiple battery cells connected in series and arranged along a first direction. A busbar is disposed on the back surface of at least one of the solar cells. An insulating strip is disposed between the busbar and the battery cell. Both the busbar and the insulating strip extend along the second direction, and the first direction intersects with the second direction. The insulating strip includes a substrate and an adhesive layer disposed on one or both sides of the substrate in the thickness direction. The insulating strip has a breakdown voltage ≥100V and a reflectivity ≥65% in the wavelength range of 800nm ​​to 1100nm.

2. A solar cell module according to claim 1, characterized in that, The thickness of the adhesive layer is greater than the thickness of the substrate, and the total thickness of the insulating strip is at least 2.5 times the thickness of the substrate.

3. A solar cell module according to claim 1, characterized in that, The total thickness of the insulating strip is 85μm to 220μm.

4. A solar cell module according to claim 1, characterized in that, The adhesive layer is any one of the following: acrylic layer, silicone layer, POE layer, EVA layer, and PVB layer.

5. A solar cell module according to claim 1, characterized in that, The substrate includes an insulating base layer and a reflective layer disposed on at least one side of the insulating base layer in the thickness direction.

6. A solar cell module according to claim 5, characterized in that, The insulating base layer is any one of PET layer, PI layer, POE layer, EVA layer, and PVB layer.

7. A solar cell module according to claim 5, characterized in that, The insulating base layer is a PET layer or a PI layer, and the adhesive layer includes a first EVA layer and a second EVA layer respectively disposed on both sides of the substrate thickness direction.

8. A solar cell module according to claim 1, characterized in that, The thermal shrinkage rate of the substrate along the first direction is ≤10%, and the thermal shrinkage rate of the substrate along the second direction is ≤10%.

9. A solar cell module according to claim 1, characterized in that, The battery string includes a first battery string and a second battery string arranged in a second direction and connected in series. Both the first battery string and the second battery string are provided with a first battery cell and a second battery cell arranged in a first direction. The first battery cell is located at the end of the battery string in which it is located. The same busbar and the same insulating strip extend from the second battery cell in the first battery string to the second battery cell in the second battery string. The busbar is located at the end of the second battery cell near the first battery cell. The first battery cell and the busbar are electrically connected by a first welding strip.

10. A solar cell module according to claim 1, characterized in that, The battery string includes a third battery string and a fourth battery string arranged in parallel along a first direction. Each battery string includes battery cells connected in series. Each battery cell includes a third battery cell and a fourth battery cell arranged along the first direction. The fourth battery cell is located at the end of the battery string in which it is located, and the fourth battery cells in the third battery string and the fourth battery string are arranged adjacent to each other in the first direction. The busbar is located at the edge of the third battery cell in the third battery string. The battery assembly also includes a second solder strip, which electrically connects the busbar, the fourth battery cell in the third battery string, and the fourth battery cell in the fourth battery string.

11. A photovoltaic system, characterized in that, Includes the battery assembly according to any one of claims 1 to 10.

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