Battery with unilateral bus bar structure and battery pack

Abstract

The utility model discloses a battery with a unilateral bus bar structure and a battery pack, the battery comprises a battery piece, a metal grid line and a unilateral bus bar, the unilateral bus bar is connected with the side surface of the battery piece, one unilateral bus bar is arranged on the same side surface of the battery piece, and the metal grid line is connected with the unilateral bus bar. And one single-side bus bar is arranged close to the edge of the side surface of the battery piece. Only one single-side bus bar is arranged on one side face of the battery piece, a traditional mode that the battery piece is designed into a symmetrical double-side single-side bus bar is replaced, the light blocking area of the bus bar can be reduced, and the photoelectric conversion efficiency can be improved.

Description

Technical Field

[0001] The utility model relates to the technical field of manufacturing crystalline silicon solar cell sheets, in particular to a battery and a battery pack with a single-side busbar structure. Background Art

[0002] At present, the process of making photovoltaic cells into components generally adopts the series welding process. There will be metal electrodes on the surface of photovoltaic cells. The positive and negative electrodes of the cells are connected in series by welding, and then covered with EVA or POE film, backing plate and other protective cells, and finally covered with glass for high-temperature lamination to ensure that the cells in the components will not be corroded by water vapor, and will not be damaged by flying sand and stones in the environment, which will reduce the output power of the solar cell module or even completely fail. Although it is effective, the photoelectric conversion efficiency of the cell cannot be improved because it cannot reduce the shading area and reduce the contact resistance. In addition, due to the rising price of silver paste, the cost of photovoltaic power generation cannot be significantly reduced.

[0003] Therefore, in recent years, the industry has actively promoted the use of copper metal grid lines to replace silver paste grid lines, and has gradually obtained verification, that is, electroplated copper grid lines replace 20um or thinner line widths. But this is not enough to meet the needs of improving efficiency and reducing costs. One of the main reasons is that the requirement for fine lines should not only be for the development of fine grid lines (finger) on the battery cell, but also for the line design of the main grid line (bus-bar, abbreviated as BB) in the module packaging stage. In the past, due to the high resistance value of silver paste grid lines, they have developed to 12BB, 18BB or even more BB numbers. This is mainly because the increase in the number of BBs can reduce the loss of current transmitted by the fine grid lines and reduce the width of the BB grid lines. However, such a design is actually still unable to completely achieve the de-silvering and simplify the overall module square installation process. Another direction is the so-called 0BB design, that is, there is no BB grid line structure on the battery cell, and the entire battery cell uses fine grid lines (Finger lines) as the collection and transmission of current. Although the amount of silver paste used for BB is really saved, the silver paste for fine grid lines is still needed. Moreover, this must be combined with the precise alignment and superposition of the string welding rods. The thinner the line width, the more difficult the alignment and superposition. However, when performing string welding of battery cells, the minimum size of the string welding rod used is 220um~250um and the width of the solder covered on the battery cell after melting must be added. Basically, it is thought that a low shading rate is achieved on the fine grid lines, but it is eventually doubled back during module packaging, which is one of the sources of CTM loss. Utility Model Content

[0004] The utility model aims to provide a battery and a battery pack with a single-side busbar structure to overcome the above disadvantages.

[0005] In order to achieve the above purpose, the technical solution adopted by the utility model is: a battery with a single-sided busbar structure, including a battery cell, a metal grid line and a single-sided busbar, the single-sided busbar is connected to the side of the battery cell, and one of the single-sided busbars is arranged on the same side of the battery cell, and one of the single-sided busbars is arranged close to the edge of the side of the battery cell. By only arranging one single-sided busbar on one side of the battery cell, instead of the traditional design of the battery cell with symmetrical double-sided single-sided busbars, the light-blocking area of ​​the busbar can be reduced while improving the photoelectric conversion efficiency.

[0006] Furthermore, the side of the battery cell includes a front side of the battery cell and a back side of the battery cell. A front single-sided bus bar is arranged on the front side of the battery cell, located at one end of the front side of the battery cell and connected to a metal grid line arranged on the front side of the battery cell; a back single-sided bus bar is arranged on the back side of the battery cell, located at one end of the back side of the battery cell and connected to a metal grid line arranged on the back side of the battery cell. The front single-sided bus bar and the back single-sided bus bar are located at two ends of the battery cell away from each other.

[0007] Furthermore, the material of the metal grid line is electroplated copper. The present application replaces the metal grid line printed with silver paste with electroplated copper metal grid lines. Because the resistivity Rs (series resistance) of the electroplated copper is only half of that of the silver paste grid line cell or even lower, the current generated by the photoelectric conversion efficiency of the battery will be converged to the single-sided bus bar for output, and the loss is smaller. And because of the high conductivity, there is no need to prepare a battery string using the existing technology of connecting string welding rods across the cell. A truly low shading rate and high conductivity solar cell module. Furthermore, in terms of reliability, the probability of hidden cracks in the cell is also reduced.

[0008] Further, the metal grid line and the single-sided bus bar are connected as one body, the width of the metal grid line is 10um to 50um, and the thickness of the metal grid line is 10um to 50um; the width of the single-sided bus bar is 0.05mm to 30mm, and the thickness of the single-sided bus bar is 10um to 50um. Exemplarily, the width of the metal grid line is 10um, 20um, 30um, 40um, 50um; the thickness of the metal grid line is 10um, 20um, 30um, 40um, 50um; the width of the single-sided bus bar is 0.05mm, 0.1mm, 1mm, 5mm, 10mm, 15mm, 20mm, 25mm, 30mm, and the thickness of the single-sided bus bar is 10um, 20um, 30um, 40um, 50um.

[0009] Furthermore, it also includes a reinforcement line arranged in a vertical or parallel direction with the single-sided bus bar, the width of the reinforcement line is greater than the width of the metal grid line and less than the width of the single-sided bus bar, the width of the reinforcement line is 50um to 500um, and the thickness of the reinforcement line is 10um to 50um. Exemplarily, the width of the reinforcement line is 50um, 100um, 200um, 300um, 400um, 500um, and the thickness of the reinforcement line is 10um, 20um, 30um, 40um, 50um.

[0010] Further, the isolation width between the single-sided bus bar and the edge of the battery cell is 0.03 mm to 30 mm. Exemplarily, the isolation width between the single-sided bus bar and the edge of the battery cell is 0.03 mm, 0.05 mm, 0.1 mm, 1 mm, 5 mm, 10 mm, 15 mm, 20 mm, 25 mm, or 30 mm.

[0011] Furthermore, the single-sided bus bar is arranged near the edge of the battery cell, and the reinforcement lines respectively arranged near the other three edges of the battery cell are connected end to end to form a rectangle, and a plurality of metal grid lines arranged perpendicularly or parallel to the single-sided bus bar are arranged in the rectangular area.

[0012] Furthermore, at least one reinforcement line is arranged in the rectangular area, and the reinforcement line and the metal grid line are arranged parallel or perpendicularly.

[0013] Further, at the connection between the metal grid and the single-sided bus bar, a widened portion is provided on the metal grid, the widened portion is integrally connected to the metal grid and the single-sided bus bar, and the shape of the widened portion is rectangular, circular, triangular or rhombus; or at the connection between the metal grid and the single-sided bus bar, an extension portion extending in the direction of the metal grid is provided on the single-sided bus bar, and the length of the extension portion ranges from 0.05mm to 50mm. Exemplarily, the length of the extension portion is 0.05mm, 0.1mm, 0.5mm, 1mm, 5mm, 10mm, 20mm, 30mm, 40mm, 50mm.

[0014] A battery pack includes the battery cell as described above, and also includes a series welding rod connecting two adjacent battery cells, wherein one end of the series welding rod is connected to a single-side bus bar of the battery cell, and the other end is connected to a single-side bus bar of another battery cell.

[0015] The beneficial effects of the utility model are:

[0016] 1) By providing only one single-sided bus bar on one side of the cell, instead of the traditional design of the cell with symmetrical double-sided single-sided bus bars, the light-blocking area of ​​the bus bar can be reduced while improving the photoelectric conversion efficiency.

[0017] 2) By replacing the silver paste printed metal grid lines with electroplated copper metal grid lines, the current generated by the photoelectric conversion efficiency of the battery is converged to the single-side bus bar for output with less loss, thereby improving the conductivity of the metal grid lines. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and the description thereof are used to explain the present invention and do not constitute an improper limitation on the present invention.

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0020] Figure 1 A schematic diagram of a battery pack according to an embodiment of the present utility model;

[0021] Figure 2 A schematic diagram of a battery according to an embodiment of the present utility model;

[0022] Figure 3 This is a schematic diagram of the connection between a single-side bus bar, a reinforcement wire and a metal grid wire according to an embodiment of the utility model;

[0023] Figure 4 This is a schematic diagram of the connection between a single-side bus bar, a reinforcement wire and a metal grid wire in another embodiment of the utility model;

[0024] Figure 5 This is a schematic diagram of the connection between a single-side bus bar, a reinforcement wire and a metal grid wire according to another embodiment of the utility model;

[0025] Figure 6 This is a schematic diagram of the connection between a single-side bus bar, a reinforcement wire and a metal grid wire in another embodiment of the utility model;

[0026] Figure 7 This is a schematic diagram of a widening portion of yet another embodiment of the utility model;

[0027] Figure 8 It is a schematic diagram of an extension portion of yet another embodiment of the utility model.

[0028] In the figure: 1. Battery cell; 11. Front side of battery cell; 12. Back side of battery cell; 2. String welding rod; 3. Single-sided bus bar; 31. Single-sided bus bar on the front side; 32. Single-sided bus bar on the back side; 4. Reinforcement line; 5. Metal grid line; 6. Widened part; 7. Extended part. DETAILED DESCRIPTION

[0029] In order to make the above-mentioned purposes, features and advantages of the utility model more obvious and easy to understand, the specific implementation methods of the utility model are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the utility model. However, the utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the utility model, so the utility model is not limited by the specific embodiments disclosed below.

[0030] See attached Figure 1-4 As shown, a battery pack in this embodiment includes a plurality of battery cells 1, and a single-sided bus bar 3 and a metal grid line 5 are provided on the front and back sides of the battery cells 1. The single-sided bus bar 3 of the present application refers to a bus bar that is only provided at one end of the front side 11 or the back side 12 of the battery cell, and corresponds to the traditional double-sided bus bar provided at both ends of the battery cell 1. The metal grid line 5 is used to collect the positive and negative currents generated by the photoelectric effect, and then collect them to the single-sided bus bar 3. The output of the single-sided bus bar 3 is connected in series with the other side of the other battery cells 1, thus forming a battery cell string group.

[0031] Specifically, a front single-sided bus bar 31 is provided on the front of the battery cell 1, located at one end of the front of the battery cell 11, and connected to the metal grid line 5 provided on the front of the battery cell 11; a back single-sided bus bar 32 is provided on the back of the battery cell 1, located at one end of the back of the battery cell 12, and connected to the metal grid line 5 provided on the back of the battery cell 12. The battery pack also includes a welding rod 2 connecting two adjacent battery cells 1, one end of the welding rod 2 is connected to the front single-sided bus bar 31 of the battery cell 1, and the other end is connected to the back single-sided bus bar 32 of another battery cell 1. The battery cells 1 connected in sequence by the welding rod 2 constitute a battery pack. The front single-sided bus bar 31 and the back single-sided bus bar 32 are located at two ends of the battery cell 1 that are far away from each other, so as to facilitate the connection of the welding rod 2, reduce the length of the welding rod 2, and reduce the resistance of the welding rod 2.

[0032] In some embodiments, the material of the metal grid line 5 is electroplated copper, replacing the metal grid line printed with silver paste. Because the resistivity Rs (series resistance) of the electroplated copper is only half of that of the silver paste grid line cell 1 or even lower, the current generated by the photoelectric conversion efficiency of the battery will be converged to the busbar for output with less loss. It is precisely because of the high conductivity of electroplated copper that there is no need to use the existing technology of connecting the string welding rod 2 across the cell 1 to prepare the battery string. The string welding rod 2 is connected to the single-sided busbar 3 set at one end of the cell 1 to prepare the battery pack, which truly achieves a solar cell module with low shading rate and high conductivity. Furthermore, in terms of reliability, the probability of hidden cracks in the cell 1 is also reduced.

[0033] In some embodiments, the metal grid line 5 and the single-sided bus bar 3 are connected as one body, and the metal grid line 5 and the single-sided bus bar 3 are simultaneously prepared by electroplating process, the width of the metal grid line 5 is 10um-50um, and the thickness of the metal grid line 5 is 10um-50um; the width of the single-sided bus bar 3 is 0.05mm-30mm, and the thickness of the single-sided bus bar 3 is 10um-50um. The single-sided bus bar 3 is used to connect with the welding bar, so as to solve the problem that the metal grid line 5 is narrow in width and difficult to align and overlap with the welding bar.

[0034] In some embodiments, a reinforcement line 4 is further included which is arranged in a vertical or parallel direction with the single-sided bus bar 3, the width of the reinforcement line 4 is 50um to 500um, the thickness of the reinforcement line 4 is 10um to 50um, the width of the reinforcement line 4 is greater than the width of the metal grid line 5, and less than the width of the single-sided bus bar 3. By setting the reinforcement line 4, the uniformity of the electroplating thickness can be increased, the stress can be dispersed, and the firmness of the connection between the metal grid line 5 and the single-sided bus bar 3 can be increased.

[0035] In some embodiments, the isolation width from the edge of the battery cell 1 ranges from 0.03 mm to 30 mm, that is, the distance between the single-sided bus bar 3 and the edge of the battery cell 1 is 0.03 mm to 30 mm.

[0036] In some embodiments, the single-sided bus bar 3 is arranged near the long edge of the battery cell 1, and reinforcement lines 4 are respectively arranged at the other three edges near the battery skin. The three reinforcement lines 4 and the single-sided bus bar 3 are connected at the ends to form a rectangle.

[0037] See attached Figure 3 and attached Figure 4 As shown, in some embodiments, a plurality of metal grid lines 5 perpendicular to the single-sided bus bar 3 are arranged in the rectangular area, one end of the metal grid line 5 is connected to the single-sided bus bar 3, and the other end is connected to the reinforcement line 4.

[0038] In some implementations, at least one reinforcement line 4 is disposed in the rectangular area, and the reinforcement line 4 and the metal grid line 5 are disposed parallel or perpendicular to each other. Figure 3 As shown, three reinforcement lines 4 are arranged in parallel with the metal grid lines 5 in the rectangular area; see FIG. Figure 4 As shown, a reinforcement line 4 is arranged in the rectangular area and is arranged perpendicular to the metal grid line 5. The arrangement of the reinforcement line 4 increases the firmness of the connection between the single-sided bus bar 3 and the metal grid line 5, and reduces the stress between the metal grid line 5 and the single-sided bus bar 3.

[0039] In some embodiments, see Appendix Figure 5 and attached Figure 6As shown, the metal grid line 5 is arranged in parallel with the single-sided bus bar 3, and at least one reinforcement line 4 is arranged in the rectangular area, and the reinforcement line 4 is arranged parallel or perpendicular to the metal grid line 5. The metal grid line 5 collects the positive and negative currents generated by the photoelectric effect, and flows back to the single-sided bus bar 3 through the reinforcement line 4.

[0040] In some embodiments, the metal grid lines 5 are arranged parallel to or perpendicular to the single-sided bus bars 3 and staggered in a checkerboard distribution.

[0041] In some embodiments, see Appendix Figure 7 As shown, at the connection between the metal grid line 5 and the single-sided bus bar 3, a widening portion 6 is provided on the metal grid line 5, and the widening portion 6 is integrally connected to the metal grid line 5 and the single-sided bus bar 3, and the shape of the widening portion 6 is rectangular, circular, triangular or rhombus. By setting the widening portion 6, the right-angle stress concentration at the junction of the metal grid line 5 and the single-sided bus bar 3 can be eliminated, and the overlapping area of ​​the single-sided bus bar 3 and the welding strip is increased when the subsequent batteries are connected in series, the connection stability of the heat exchange welding strip of the single-sided bus bar 3 is improved, and the contact resistance between the welding strip and the single-sided bus bar 3 is reduced.

[0042] In some embodiments, see Appendix Figure 8 As shown, at the connection between the metal grid line 5 and the single-sided bus bar 3, an extension portion 7 extending in the direction of the metal grid line 5 is provided on the single-sided bus bar 3, and the length of the extension portion 7 ranges from 0.05 mm to 50 mm. The extension portion 7 is used for series welding with the welding rod, further improving the connection stability of the heat exchange welding rod of the single-sided bus bar 3 and reducing the contact resistance between the welding rod and the single-sided bus bar 3.

[0043] The above implementation modes are only for illustrating the technical concept and features of the utility model, and their purpose is to allow people familiar with this technology to understand the content of the utility model and implement it. It cannot be used to limit the protection scope of the utility model. Any equivalent changes or modifications made according to the spirit of the utility model should be included in the protection scope of the utility model.

Claims

1. A battery with a single-sided busbar structure, comprising a battery cell (1), characterized in that: It also comprises a metal grid line (5) and a single-sided bus bar (3), wherein the single-sided bus bar (3) is connected to the side of the battery cell (1), one of the single-sided bus bars (3) is arranged on the same side of the battery cell (1), and one of the single-sided bus bars (3) is arranged close to the edge of the side of the battery cell (1).

2. The battery with a single-side bus bar structure according to claim 1, characterized in that: The side surface of the battery cell (1) comprises a front side (11) and a back side (12) of the battery cell; the front side (11) of the battery cell is provided with a front single-sided bus bar (31), which is located at one end of the front side (11) of the battery cell and is connected to a metal grid line (5) provided on the front side (11) of the battery cell; the back side (12) of the battery cell is provided with a back single-sided bus bar (32), which is located at one end of the back side (12) of the battery cell and is connected to a metal grid line (5) provided on the back side (12) of the battery cell; the front single-sided bus bar (31) and the back single-sided bus bar (32) are located at two ends of the battery cell (1) that are away from each other.

3. The battery with a single-side bus bar structure according to claim 1, characterized in that: The material of the metal grid line (5) is electroplated copper.

4. The battery with a single-side bus bar structure according to claim 1, characterized in that: The metal grid line (5) and the single-sided bus bar (3) are connected as one piece; the width of the metal grid line (5) is 10 um to 50 um, and the thickness of the metal grid line (5) is 10 um to 50 um; the width of the single-sided bus bar (3) is 0.05 mm to 30 mm, and the thickness of the single-sided bus bar (3) is 10 um to 50 um.

5. The battery with a single-side bus bar structure according to claim 1, characterized in that: It also includes a reinforcement line (4) arranged in a vertical or parallel direction with the single-sided bus bar (3), the width of the reinforcement line (4) is greater than the width of the metal grid line (5) and less than the width of the single-sided bus bar (3), the width of the reinforcement line (4) is 50 um to 500 um, and the thickness of the reinforcement line is 10 um to 50 um.

6. The battery with a single-side bus bar structure according to claim 1, characterized in that: The isolation width between the single-sided bus bar (3) and the edge of the battery cell (1) is 0.03 mm to 30 mm.

7. The battery with a single-side bus bar structure according to claim 5, characterized in that: The single-sided bus bar (3) is arranged near the edge of the battery cell (1), and the reinforcement lines (4) respectively arranged near the other three edges of the battery cell (1) are connected end to end to form a rectangle, and a plurality of metal grid lines (5) arranged perpendicularly or parallel to the single-sided bus bar (3) are arranged in the rectangular area.

8. The battery with a single-side bus bar structure according to claim 7, characterized in that: At least one reinforcement line (4) is arranged in the rectangular area, and the reinforcement line (4) and the metal grid line (5) are arranged parallel or perpendicularly.

9. The battery with a single-side bus bar structure according to claim 1, characterized in that: At the connection point between the metal grid line (5) and the single-sided bus bar (3), a widened portion (6) is provided on the metal grid line (5), the widened portion (6) and the metal grid line (5) and the single-sided bus bar (3) are integrally connected, and the shape of the widened portion (6) is rectangular, circular, triangular or diamond-shaped; or at the connection point between the metal grid line (5) and the single-sided bus bar (3), an extension portion (7) extending in the direction of the metal grid line (5) is provided on the single-sided bus bar (3), and the length of the extension portion (7) ranges from 0.05 mm to 50 mm.

10. A battery pack, comprising a plurality of battery cells according to any one of claims 1 to 9, the battery pack further comprising a string welding rod (2) connecting two adjacent battery cells (1), one end of the string welding rod (2) being connected to a single-sided bus bar (3) of a battery cell (1), and the other end of the string welding rod (2) being connected to a single-sided bus bar (3) of another battery cell (1).

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