Battery assembly and photovoltaic system

Abstract

The invention is applicable to the field of photovoltaic technology, and provides a battery assembly and a photovoltaic system, the battery assembly comprises a front adhesive film, a back adhesive film and a battery string; the battery string comprises a plurality of battery pieces which are arranged in an overlapping manner along a first direction, and each battery piece comprises a first edge and a second edge which are opposite; a first chamfer is arranged at the first edge of the backlight surface of each battery piece, the first chamfer is inclined from the backlight surface of the battery piece to the side surface of the battery piece, and the backlight surface of one battery piece at the first edge and the light facing surface of the adjacent battery piece at the second edge are lapped through the surface of the first chamfer; the back adhesive film is arranged on the shady face of the battery piece, and the front adhesive film is arranged on the light-facing face of the battery piece. The contact between the right-angle sharp point at the first edge and the adjacent battery piece is avoided, the stress concentration at the contact position is avoided, and the subfissure problem caused by the stress concentration is effectively avoided.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of photovoltaic, and particularly relates to a battery assembly and a photovoltaic system. BACKGROUND

[0002] In the prior art, a battery assembly is usually composed of a front adhesive film, a back adhesive film and a battery string. Figure 1 and Figure 2 As shown in the drawings, when the battery pieces in the battery string are arranged in an overlapping manner, the battery pieces are prone to hidden cracks due to stress concentration between adjacent battery pieces and other problems. The hidden cracks of the battery pieces affect the photoelectric conversion efficiency of the battery assembly, reduce the service life of the battery assembly, and may even cause the battery assembly to fail. Therefore, how to avoid hidden cracks of the battery pieces during use is a problem to be solved in the field. SUMMARY

[0003] The present application provides a battery assembly and a photovoltaic system, aiming to solve the problem of hidden cracks of battery pieces when the battery pieces are stacked.

[0004] The present application is implemented as follows: a battery assembly comprises a front adhesive film, a back adhesive film and a battery string. The battery string comprises a plurality of battery pieces arranged in an overlapping manner along a first direction, and the battery pieces comprise opposite first and second edges. A first chamfer is arranged at the first edge of the back light surface of the battery piece, and the first chamfer is inclined from the back light surface of the battery piece to the side surface of the battery piece. The back light surface of the first edge of a battery piece is connected to the light surface of the second edge of an adjacent battery piece through the surface of the first chamfer. The back adhesive film is arranged on the back light surface of the battery piece, and the front adhesive film is arranged on the light surface of the battery piece.

[0005] Optionally, the angle of the first chamfer is less than 45°.

[0006] Optionally, the thickness of the battery piece at the first edge is less than half of the thickness of the battery piece at a position other than the first chamfer.

[0007] Optionally, the projection of the first chamfer on the back light surface has a size in the first direction, and the size is not more than the stacking width of two adjacent battery pieces in the first direction.

[0008] Optionally, the stacking width of two adjacent battery pieces in the first direction is greater than the thickness of the battery piece at a position other than the first chamfer.

[0009] Optionally, the stacking angle of two adjacent battery pieces is not more than 10° different from the angle of the first chamfer.

[0010] Optionally, the second edge of the battery piece has a second chamfer between the adjacent edge.

[0011] Optionally, the material at the first chamfer is different from the material of the silicon substrate.

[0012] Optionally, the battery piece is a back contact battery piece.

[0013] The application also provides a photovoltaic system comprising the above battery assembly.

[0014] The application achieves the beneficial effects that the battery string is arranged between the front adhesive film and the back adhesive film, the battery string comprises a plurality of battery pieces arranged in an overlapping manner, the first chamfer is arranged at the first edge of the back surface of the battery piece, the sharp point of the right angle at the first edge is avoided from contacting the adjacent battery piece, the stress concentration at the contact position is avoided, and the hidden crack problem caused by the stress concentration is effectively avoided. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a structural schematic diagram of the battery assembly when not laminated; Figure 2 is a structural schematic diagram of the battery assembly when laminated according to the prior art; Figure 3 is a structural schematic diagram of the battery assembly when laminated according to the application; Figure 4 is a structural schematic diagram of the battery piece according to the application; Figure 5 is a top view of the battery string according to the application; Figure 6 is an enlarged schematic diagram of A.

[0016] 100, battery assembly; 110, battery string; 111, battery piece; 1111, first edge; 1112, second edge; 1113, first chamfer; 1114, second chamfer; 1115, arc part; 1116, flat part; 120, front adhesive film; 130, back adhesive film. DETAILED DESCRIPTION

[0017] In order to make the objectives, technical solutions and advantages of the application clearer, the application will be further described in detail below with reference to the accompanying drawings and embodiments. The embodiments shown in the drawings are exemplary and are only used to explain the application, and cannot be understood as a limitation of the application. In addition, it should be understood that the specific embodiments described herein are only used to explain the application and cannot be used to limit the application.

[0018] In the description of the application, it should be understood that the terms "length", "width", "upper", "lower", "left", "right", "horizontal", "top", "bottom", and the like are intended to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the application.

[0019] In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the application, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified and limited.

[0020] In the description of the application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected or can communicate with each other; it can be directly connected, or indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the application can be understood according to the specific circumstances.

[0021] In the present application, unless otherwise explicitly specified and limited, the "upper" or "lower" of the first feature to the second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the "above", "over" and "on" of the first feature to the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The "below", "under" and "under" of the first feature to the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0022] The following disclosure provides many different embodiments, or examples, for implementing different structures of the present application. For the purpose of simplification, the elements and arrangements of the particular examples are described in the following disclosure. Of course, they are merely examples and are not intended to limit the present application. Moreover, the present application can repeatedly refer to reference numerals and / or reference letters in different examples, and such repetition is for the purpose of simplification and clarity, and does not indicate a relationship between the various embodiments and / or arrangements being discussed. In addition, the present application provides examples of various specific processes and materials, but those of ordinary skill in the art can realize the application of other processes and / or the use of other materials.

[0023] The present application is because the battery string is arranged between the front adhesive film and the back adhesive film, the battery string includes a plurality of battery pieces arranged in an overlapping manner, a first chamfer is arranged at the first edge of the back light surface of the battery piece, the straight angle tip at the first edge is avoided from contacting the adjacent battery piece, stress concentration at the contact position is avoided, and the hidden crack problem caused by stress concentration is effectively avoided.

[0024] Example One As shown in Figure 3 and Figure 4 The present embodiment provides a battery assembly 100, which includes a front adhesive film 120, a back adhesive film 130, and a battery string 110. The battery string 110 includes a plurality of battery pieces 111 arranged in an overlapping manner along a first direction, and the battery piece 111 includes opposite first and second edges 1111 and 1112. A first chamfer 1113 is arranged at the first edge 1111 of the back light surface of the battery piece 111, the first chamfer 1113 is inclined from the back light surface of the battery piece 111 to the side surface of the battery piece 111, and the back light surface of the first edge 1111 of a battery piece 111 is connected to the surface of the light surface of the second edge 1112 of an adjacent battery piece 111 through the first chamfer 1113. The back adhesive film 130 is arranged on the back light surface of the battery piece 111, and the front adhesive film 120 is arranged on the light surface of the battery piece 111.

[0025] The battery string 110 includes a plurality of battery pieces 111, the battery piece 111 has opposite first and second edges 1111 and 1112, and has opposite light and back light surfaces, the plurality of battery pieces 111 are arranged in an overlapping manner along a first direction, the back light surface of the first edge 1111 of a battery piece 111 is connected to the light surface of the second edge 1112 of an adjacent battery piece 111, and the plurality of battery pieces 111 are arranged in an extending manner along the first direction. Specifically, the battery piece 111 can be a back contact battery, the electrode is arranged on the back surface of the back contact battery, the front grid line is eliminated, and higher photoelectric conversion efficiency is achieved.

[0026] It should be noted that during the manufacturing process of the battery assembly 100, the battery string 110 is positioned between the backing film 130 and the front film 120, with the backlight side of the battery cell 111 facing the backing film 130 and the light-facing side facing the front film 120. The front film 120 is typically pre-crosslinked. Pre-crosslinking refers to the process of forming a certain degree of crosslinking between some molecules in the front film 120 through specific techniques. This pre-crosslinking process gives the front film 120 a relatively stable shape and low flowability during lamination. The backing film 130, however, is not pre-crosslinked or has a low degree of crosslinking, making it more prone to flow during lamination. Due to the lower flowability of the pre-crosslinked front film 120, it acts as a stable carrier during lamination, providing a relatively fixed support platform for the battery cell 111. The battery cell 111 is subjected to a force in the direction of the front adhesive film 120. The light-facing surface of the battery cell 111 is tightly bonded to the front adhesive film 120. In the overlapping part of the battery cells 111, the upper battery cell 111 is blocked by the lower battery cell 111 and deforms, warping in the direction of the back adhesive film 130.

[0027] Specifically, solar cells A and B are arranged adjacently and overlapping, with the light-facing surface of solar cell A in contact with the backlight surface of solar cell B. The second edge 1112 of solar cell A warps towards the adhesive film 130 due to the obstruction of the first edge 1111 of solar cell B. When the first edge 1111 of the backlight surface of solar cell B is a right angle, when solar cell A warps, its light-facing surface directly contacts the sharp point of the right angle. Under the same external force, the smaller the force-bearing area, the greater the pressure. The smaller the force-bearing area at the sharp point, the greater the pressure during lamination. The extremely high pressure applied to the light-facing surface of solar cell A can easily damage it.

[0028] A first chamfer 1113 is provided at the first edge 1111 of the backlight surface of the battery cell 111. The first chamfer 1113 is inclined from the backlight surface of the battery cell 111 to the side of the battery cell 111. That is, a battery cell B overlaps with the battery cell A on the backlight surface of the first edge 1111 through the surface of the first chamfer 1113 of the battery cell A. The contact between the battery cell A and the battery cell B changes from line contact to surface contact, which increases the force-bearing area. Under the condition that the lamination pressure remains unchanged, the pressure on the light-facing surface of the battery cell A is reduced, so as to prevent the light-facing surface of the battery cell A from being damaged by the battery cell B.

[0029] In this embodiment, the battery string 110 is disposed between the front adhesive film 120 and the back adhesive film 130. The battery string 110 includes a plurality of battery cells 111 arranged in an overlapping manner. A first chamfer 1113 is provided at the first edge 1111 of the back surface of the battery cell 111 to prevent the right-angled sharp point at the first edge 1111 from contacting the adjacent battery cell 111, thereby avoiding stress concentration at the contact position and effectively avoiding the problem of microcracks caused by stress concentration.

[0030] In some embodiments, the angle of the first chamfer 1113 is less than 45°. It can be imagined that a portion of the edge of the backlight surface of the solar cell 111 is shaved off to form an inclined surface. The first chamfer 1113 is located on the backlight surface, and the first chamfer 1113 refers to the angle (less than 90°) between the inclined surface and the backlight surface. Several solar cells 111 are arranged in a staggered, overlapping pattern. Typically, the solar cells 111 are relatively thin, and the overlapping angle of the solar cells 111 is small. With the first chamfer 1113 less than 45°, the inclined surface forming the chamfer has a gentle slope, resulting in a smoother contact between the two solar cells 111 and a larger contact area.

[0031] In some embodiments, the thickness of the battery sheet 111 at the first edge 1111 is less than half the thickness of the battery sheet 111 at locations other than the first chamfer 1113. The battery sheet 111 has a first chamfer 1113, meaning a chamfer has been cut off from the battery sheet 111, corresponding to the first chamfer 1113. The length of the chamfer along the thickness direction of the battery sheet 111 is the first side length of the chamfer, and the length of the chamfer along the first direction of the battery sheet 111 is the second side length of the chamfer. The thickness of the battery sheet 111 at the first edge 1111 is also the thickness of the battery sheet 111 minus the first side length. It can be understood that the thickness of the battery sheet 111 is the thickness of the battery sheet 111 itself before the chamfer is applied. The thickness difference across the battery sheet 111 is small and can be considered uniform. That is, the thickness of the battery sheet 111 is the thickness of the battery sheet 111 at other locations before the chamfer is applied, i.e., the thickness of the battery sheet 111 at locations other than the first chamfer 1113. The thickness of the battery cell 111 at the first edge 1111 is less than half the thickness of the battery cell 111 at positions other than the first chamfer 1113. That is, the length of the first side of the chamfer is greater than half the thickness of the battery cell 111, and a deep cut is made at the edge of the backlight surface of the battery cell 111. Because the battery cell 111 itself is relatively thin, when the thickness at the first chamfer 1113 position is greater than half the thickness of the battery cell 111, the chamfer is small, difficult to control, and results in a large cutting error. However, when the thickness at the first chamfer 1113 position is less than half the thickness of the battery cell 111, although there will be some error during cutting, this error is within an acceptable range.

[0032] In some embodiments, the projection of the first chamfer 1113 onto the backlight surface along the first direction does not exceed the stacking width of two adjacent battery cells 111 in the first direction. The stacking width of two adjacent battery cells 111 in the first direction is the overlapping dimension of their projections onto the backlight surface along the first direction, i.e., the width of the overlapping area of ​​the two battery cells 111. In other words, the second side length of the chamfer is less than or equal to the width of the overlapping area of ​​the two battery cells 111, which ensures the stability of the battery cells 111 during the stacking process. If the chamfer length is too long, it may reduce the contact area between the battery cells 111 during stacking, affecting the stability of the electrical and mechanical connections between the battery cells 111, and may even lead to a loose stacking structure, reducing the performance and reliability of the battery assembly 100.

[0033] In some embodiments, the stack width of two adjacent solar cells in a first direction is greater than the thickness of solar cell 111 at a location other than the first chamfer 1113. That is, the width of the overlapping area of ​​the two solar cells 111 is greater than the thickness of the solar cell 111. A stack width greater than the thickness of the solar cell 111 provides a stronger mechanical connection. When the battery assembly 100 is subjected to external mechanical forces, a larger stack width can better disperse stress, prevent relative displacement or separation between the solar cells 111, and improve the mechanical stability and impact resistance of the battery assembly 100.

[0034] In some embodiments, the difference between the stacking angle of two adjacent battery cells 111 and the angle of the first chamfer 1113 does not exceed 10°. The stacking angle refers to the angle between the warped portion of the battery cell 111 in the battery string 110 and the placement plane (front adhesive film 120), specifically, as... Figure 6 As shown, the warped portion includes an arc portion 1115 and a flat portion 1116, which are connected. The stacking angle is specifically the angle between the flat portion 1116 and the placement plane, as shown... Figure 6 In the context of α, it can be understood that the greater the curvature of the arc portion 1115, the greater the angle between the flat portion 1116 and the placement plane. It should be noted that in a string of batteries 110, the first battery cell 111 does not stack on top of the other battery cells 111, and the first battery cell 111 does not have a stacking angle; therefore, the first battery cell 111 needs to be excluded when discussing the stacking angle.

[0035] In a string of batteries 110, the stacking angles of each battery cell 111 are different. Because the angle between the previous battery cell 111 and the placement plane is different, the stacking angles of several battery cells 111 are different. For example, the second battery cell 111 is stacked on top of the first battery cell 111, and the angle between the first battery cell 111 and the placement plane is 0. The third battery cell 111 is stacked on top of the second battery cell 111, and the angle between the second battery cell 111 and the placement plane is not 0. The stacking angles of the third battery cell 111 and the second battery cell 111 are different.

[0036] The stacking angles of different cells 111 in a battery string 110 are relatively small. Specifically, the difference between the stacking angle of any single cell 111 and the first chamfer 1113 angle is no more than 10°. Alternatively, the difference between the average stacking angle of several cells 111 in a battery string 110 and the first chamfer 1113 angle is no more than 10°. During the battery module 100 encapsulation process, similar stacking angles and the first chamfer 1113 angle ensure the encapsulation consistency of the cells 111. This helps improve the stability and reliability of the encapsulation process, reduces encapsulation defects caused by angle differences, and improves the yield and quality of the battery module 100.

[0037] like Figure 4 and Figure 5 As shown, in some embodiments, the second edge 1112 of the battery cell 111 has a second chamfer 1114 between it and the adjacent edge. Before the second chamfer 1114 is provided, the battery cell 111 is a rectangle in top view, and the provision of the first chamfer 1113 does not affect the outer contour shape of the battery cell 111 in top view. The first edge 1111 and the second edge 1112 are opposite to each other, and the first edge 1111 and the second edge 1112 are respectively adjacent to two other edges. The second chamfer 1114 is provided between the second edge 1112 and the adjacent edge, that is, two chamfers are provided at the apex position corresponding to the second edge 1112 of the rectangle in top view. The provision of the second chamfer 1114 can eliminate the sharp corners of the edge of the battery cell 111, reduce the risk of injury to operators during the handling, assembly or use of the battery cell 111, and improve the safety of operation.

[0038] The second edge 1112 of the solar cell 111 with a second chamfer 1114 is stacked on the first edge 1111 of the adjacent solar cell 111. After lamination, the second edge 1112 warps and deforms. The second chamfer 1114 can disperse the warping stress, thereby reducing the risk of microcracks in the solar cell 111.

[0039] In some embodiments, the material of the chamfer is different from that of the silicon substrate. Specifically, the material of the chamfer is converted to silicon oxide or amorphous silicon, which have better machinability. Monocrystalline silicon has high hardness, with a Mohs hardness of approximately 7. However, monocrystalline silicon is also a typical brittle material, prone to brittle fracture under external force, making it difficult to create chamfers on monocrystalline silicon. Compared to monocrystalline silicon, silicon oxide and amorphous silicon have better machinability and are easier to chamfer. Monocrystalline silicon can be converted to silicon oxide, commonly using thermal oxidation or plasma-enhanced chemical vapor deposition (PECVD) to convert the silicon at the chamfer into silicon oxide. Monocrystalline silicon can also be converted to amorphous silicon, commonly using physical vapor deposition (PVD) or chemical vapor deposition (CVD) to evaporate or decompose the monocrystalline silicon material into atoms or molecules, which are then deposited on a substrate to form an amorphous silicon thin film.

[0040] Example Two This embodiment provides a photovoltaic system, including the aforementioned battery module 100.

[0041] Photovoltaic systems can be applied in photovoltaic power plants, such as ground-mounted power plants, rooftop power plants, and floating power plants. They can also be applied to equipment or devices that utilize solar energy to generate electricity, such as user solar power supplies, solar streetlights, solar cars, and solar buildings. Of course, it's understandable that the application scenarios of photovoltaic systems are not limited to these; that is, photovoltaic systems can be applied in all fields that require solar energy to generate electricity. Taking a photovoltaic power generation system grid as an example, a photovoltaic system can include photovoltaic arrays, combiner boxes, and inverters. The photovoltaic array can be an array combination of multiple battery modules 100. For example, multiple battery modules 100 can form multiple photovoltaic arrays. The photovoltaic arrays are connected to combiner boxes, which can collect the current generated by the photovoltaic arrays. The collected current flows through an inverter and is converted into AC power required by the mains power grid before being connected to the mains power grid to achieve solar power supply.

[0042] The beneficial effects of the photovoltaic system in this embodiment are equivalent to the beneficial effects of the battery module 100 described above, and will not be repeated here.

[0043] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A battery assembly, characterized in that, include: Front adhesive film, back adhesive film, and battery string; The battery string includes a plurality of battery cells arranged in an overlapping manner along a first direction, and the battery cells include opposing first edges and second edges; A first chamfer is provided at the first edge of the backlight surface of the battery cell. The first chamfer is inclined from the backlight surface of the battery cell to the side surface of the battery cell. The backlight surface of one battery cell at the first edge and the light-facing surface of the adjacent battery cell at the second edge overlap through the surface of the first chamfer. The backing film is disposed on the back surface of the battery cell, and the front adhesive film is disposed on the light-facing surface of the battery cell.

2. The battery assembly as claimed in claim 1, characterized in that, The angle of the first chamfer is less than 45°.

3. The battery assembly as described in claim 1, characterized in that, The thickness of the battery cell at the first edge is less than half the thickness of the battery cell at positions other than the first chamfer.

4. The battery assembly as claimed in claim 1, characterized in that, The projection of the first chamfer onto the backlight surface along the first direction does not exceed the stack width of two adjacent solar cells in the first direction.

5. The battery assembly as claimed in claim 1, characterized in that, The stack width of two adjacent solar cells in the first direction is greater than the thickness of the solar cells at positions other than the first chamfer.

6. The battery assembly as claimed in claim 1, characterized in that, The difference between the stacking angle of two adjacent battery cells and the first chamfer angle does not exceed 10°.

7. The battery assembly as claimed in claim 1, characterized in that, The second edge of the battery cell has a second chamfer between it and the adjacent edge.

8. The battery assembly as claimed in claim 1, characterized in that, The material at the first chamfer is different from the silicon substrate material.

9. The battery assembly as claimed in claim 1, characterized in that, The battery cell is a back-contact battery cell.

10. A photovoltaic system, characterized in that, Includes the battery assembly as described in any one of claims 1 to 9.

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