Battery cell and battery string

Abstract

The utility model relates to the field of photovoltaic technology, in particular to a battery unit and a battery string. The battery unit comprises a battery piece, a bonding piece and a welding strip. A plurality of first electrodes and a plurality of second electrodes are arranged on one side of the battery piece, the first electrodes and the second electrodes extend in the first direction, the first electrodes and the second electrodes are alternately arranged in the second direction, and the first direction is perpendicular to the second direction. The first electrode includes a plurality of first pads, and the second electrode includes a plurality of second pads. The bonding piece is bonded on the battery piece along the second direction, and the bonding piece is arranged between two adjacent first bonding pads and between two adjacent second bonding pads. The welding strips comprise the first welding strip and the second welding strip, the first welding strip is connected with the first bonding pad in a welded mode, the second welding strip is connected with the second bonding pad in a welded mode, and the first welding strip and the second welding strip are both connected with the bonding piece. According to the battery unit, the phenomenon of solder strip deviation can be reduced, the stability and the reliability of connection between the solder strip and the battery piece are improved, and the cost is saved.

Description

Technical Field

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

[0002] Back-contact (BC) cells have both their emitter and base electrodes located on the back side of the cell. This design allows for greater light energy absorption on the front side of the cell, reducing light obstruction by the electrode grid lines and thus improving the cell's photoelectric conversion efficiency. Because both the emitter and base electrodes are located on the back side of the cell, the fabrication of the cell strings requires extremely high precision in the placement and fixation of the solder ribbons.

[0003] In existing technologies, the connection between the solder ribbon and the electrode of the cell in a battery string with back contact is not stable. This can easily lead to the solder ribbon shifting, thereby increasing the risk of short circuits and increasing manufacturing costs.

[0004] Therefore, there is an urgent need to design a battery cell and battery string to solve the above technical problems. Utility Model Content

[0005] The primary objective of this invention is to provide a battery cell that reduces the occurrence of solder strip misalignment, improves the stability and reliability of the connection between the solder strip and the battery cell, enhances safety, and saves costs.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] This utility model provides a battery cell, comprising:

[0008] A battery cell, wherein a plurality of first electrodes and a plurality of second electrodes are disposed on one side, the first electrodes and the second electrodes both extending along a first direction, the plurality of first electrodes being spaced apart, the plurality of second electrodes being spaced apart, and the first electrodes and the second electrodes being alternately arranged along a second direction; the first direction and the second direction are perpendicular to each other;

[0009] The first electrode includes a plurality of first pads, and the second electrode includes a plurality of second pads;

[0010] An adhesive is bonded to the battery cell along the second direction. The adhesive, the first electrode, and the second electrode are all located on the same side of the battery cell, and the adhesive is located between two adjacent first pads and between two adjacent second pads.

[0011] The solder strip includes a first solder strip and a second solder strip. The first solder strip is soldered to the first pad, and the second solder strip is soldered to the second pad. Both the first solder strip and the second solder strip extend along the first direction, and both the first solder strip and the second solder strip are connected to the adhesive.

[0012] As an optional technical solution for a battery cell, multiple first pads are arranged at equal intervals, and multiple second pads are arranged at equal intervals; the width of the adhesive is not greater than the distance between two adjacent first pads, and the width of the adhesive is not greater than the distance between two adjacent second pads.

[0013] As an alternative technical solution for battery cells, the first pad and the second pad are flush in height along the second direction.

[0014] As an optional technical solution for a battery cell, along the second direction, the length of the adhesive is not less than the distance between two adjacent first solder strips;

[0015] And / or, along the second direction, the length of the adhesive is not less than the distance between two adjacent second weld strips.

[0016] As an optional technical solution for a battery cell, the adhesive is provided in multiple forms, and the multiple adhesives are equally spaced along the first direction, and / or, the multiple adhesives are equally spaced along the second direction.

[0017] As an optional technical solution for battery cells, the adhesive is one of EVA, POE, or PVB.

[0018] As an optional technical solution for a battery cell, the thickness of the adhesive, the thickness of the first pad, and the thickness of the second pad are all equal.

[0019] As an optional technical solution for a battery cell, the battery cell is a back-contact battery.

[0020] The second objective of this invention is to provide a battery string that can reduce the occurrence of solder strip misalignment, improve the stability and reliability of the connection between the solder strip and the battery cell, and achieve the goal of cost saving.

[0021] To achieve this objective, the present invention adopts the following technical solution:

[0022] This utility model provides a battery string, which includes at least two battery cells as described in any of the technical solutions, with the edges of the two battery cells partially overlapping, wherein the front of one battery cell is connected to the back of the adjacent battery cell by an adhesive.

[0023] A first solder strip in one of the battery cells is soldered to a second electrode in an adjacent battery cell, and a second solder strip in one of the battery cells is soldered to a first electrode in an adjacent battery cell, so that two adjacent battery cells are connected in series.

[0024] As an optional technical solution for battery strings, a first busbar and a second busbar are respectively provided at both ends of the battery string. The first busbar is connected to a first solder strip on the first battery cell in the battery string, and the second busbar is connected to a second solder strip on the last battery cell in the battery string.

[0025] The beneficial effects of this utility model include at least the following:

[0026] This invention provides a battery cell comprising a battery cell, an adhesive, and solder ribbons. The battery cell has a plurality of first electrodes and a plurality of second electrodes on one side, both extending along a first direction. The first electrodes and the second electrodes are spaced apart, and are alternately arranged along a second direction; the first and second directions are perpendicular to each other. Each first electrode includes a plurality of first pads, and each second electrode includes a plurality of second pads. The adhesive is bonded to the battery cell along the second direction, located on the same side of the battery cell as the first and second electrodes. The adhesive is positioned between adjacent first pads of the same first electrode and between adjacent second pads of the same second electrode, and / or at the edge of the battery cell. The solder ribbons include first solder ribbons and second solder ribbons. The first solder ribbons are soldered to the first pads of the first electrodes, and the second solder ribbons are soldered to the second pads of the second electrodes. Both the first and second solder ribbons extend along the first direction and are connected to the adhesive.

[0027] In this invention, the first solder strip is welded to the first pad on the first electrode, and the second solder strip is welded to the second pad on the second electrode, thereby facilitating the current extraction from the solar cell. The adhesive component in this invention is located between the solder strip and the solar cell. By using the adhesive component, the first and second solder strips are bonded to the solar cell, thereby improving the stability and reliability of the first and second solder strips relative to the solar cell, reducing the risk of misalignment, reducing the risk of short circuits, improving safety, and saving costs.

[0028] Furthermore, the adhesive is located between two adjacent first pads and between two adjacent second pads. This allows the adhesive to avoid the positions of the first and second pads, thereby ensuring the welding performance of the first solder ribbon to the first pad and the welding performance of the second solder ribbon to the second pad, avoiding poor welding phenomena such as cold solder joints, and improving the stability and reliability of the connection between the solder ribbon and the solar cell. In addition, the adhesive can also be placed at the edge of the solar cell, which is beneficial for splicing multiple solar cells. This not only improves the stability and reliability of the connection between solar cells, but also reduces hard contact between solar cells, reducing the risk of scratching the solar cells.

[0029] This utility model also provides a battery string that can reduce the occurrence of solder strip misalignment, improve the stability and reliability of the connection between the solder strip and the battery cell, and achieve the purpose of saving costs. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the content of the embodiments of this utility model and these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the structure of the battery cell provided in this embodiment of the utility model;

[0032] Figure 2 This is a cross-sectional view of the battery cell provided in an embodiment of the present utility model;

[0033] Figure 3 This is a schematic diagram of the battery string structure provided in an embodiment of the present invention;

[0034] Figure 4 yes Figure 3 Enlarged view of a portion of point A in the middle;

[0035] Figure 5 This is a cross-sectional view of the battery string provided in an embodiment of this utility model.

[0036] Figure Labels

[0037] 100, Solar cell; 110, First electrode; 1101, First pad; 120, Second electrode; 1201, Second pad;

[0038] 200. Adhesive components;

[0039] 300, welding strip; 310, first welding strip; 320, second welding strip;

[0040] 400, First busbar; 500, Second busbar. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0042] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0043] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0044] In the description of this utility model, it should be noted that the terms "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this utility model is in use. They are used only for the convenience of describing this utility model and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first," "second," and "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0045] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0046] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0047] The embodiments of this utility model are described in detail below. Examples of these 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 utility model, and should not be construed as limiting this utility model.

[0048] This embodiment provides a battery cell that can reduce the occurrence of solder strip misalignment, improve the stability and reliability of the connection between the solder strip and the battery cell, enhance safety, and save costs.

[0049] like Figures 1-2 As shown, the battery cell mainly includes a battery cell 100, an adhesive component 200, and a solder ribbon 300. The battery cell 100 has several first electrodes 110 and several second electrodes 120 on one side. Both the first electrodes 110 and the second electrodes 120 extend along a first direction. The first electrodes 110 and the second electrodes 120 are spaced apart, and the first electrodes 110 and the second electrodes 120 are alternately arranged along a second direction; the first direction and the second direction are perpendicular to each other. The first electrodes 110 include multiple first solder pads 1101, and the second electrodes 120 include multiple second solder pads 1201.

[0050] The adhesive component 200 is bonded to the battery cell 100 along a second direction. The adhesive component 200, the first electrode 110, and the second electrode 120 are all located on the same side of the battery cell 100. The adhesive component 200 is located between two adjacent first pads 1101 in the same first electrode 110, and between two adjacent second pads 1201 in the same second electrode 120. And / or, the adhesive component 200 is located at the edge of the battery cell 100. The solder ribbon 300 includes a first solder ribbon 310 and a second solder ribbon 320. The first solder ribbon 310 is soldered to the first pad 1101 of the first electrode 110, and the second solder ribbon 320 is soldered to the second pad 1201 of the second electrode 120. Both the first solder ribbon 310 and the second solder ribbon 320 extend along a first direction, and both are connected to the adhesive component 200. The first direction is... Figure 1 The Y-axis direction, the second direction is Figure 1 The X-axis direction in the diagram.

[0051] Based on the above design, in this embodiment, the first solder ribbon 310 is soldered to the first solder pad 1101 on the first electrode 110, and the second solder ribbon 320 is soldered to the second solder pad 1201 on the second electrode 120, thereby facilitating the current output from the battery cell 100. In this embodiment, the adhesive 200 is located between the solder ribbon 300 and the battery cell 100. The adhesive 200 achieves the bonding connection between the first solder ribbon 310, the second solder ribbon 320, and the battery cell 100, thereby improving the stability and reliability of the first solder ribbon 310 and the second solder ribbon 320 relative to the battery cell 100, reducing the risk of misalignment of the first solder ribbon 310 and the second solder ribbon 320, reducing the risk of short circuits, improving safety, and saving costs.

[0052] In this embodiment, the adhesive 200 is located between two adjacent first pads 1101 and between two adjacent second pads 1201. This allows the adhesive 200 to avoid the positions of the first pads 1101 and the second pads 1201, thereby ensuring the welding performance of the first solder ribbon 310 to the first pad 1101 and the welding performance of the second solder ribbon 320 to the second pad 1201, avoiding poor welding phenomena such as cold solder joints, and improving the stability and reliability of the connection between the solder ribbon 300 and the battery cell 100. In addition, the adhesive 200 can also be located at the edge of the battery cell 100, which is beneficial for splicing multiple battery cells 100. This not only improves the stability and reliability of the connection between battery cells 100, but also reduces hard contact between battery cells 100, reducing the risk of scratching the battery cells 100.

[0053] Optionally, in this embodiment, the first electrode 110 can be configured as one of the positive gate line and the negative gate line, and the second electrode 120 can be configured as the other of the positive gate line and the negative gate line.

[0054] Optionally, in this embodiment, multiple adhesive members 200 are arranged at equal intervals. Specifically, the multiple adhesive members 200 are arranged at equal intervals along a first direction, and / or, the multiple adhesive members 200 are arranged at equal intervals along a second direction. This can further improve the stability and reliability of the connection between the first solder ribbon 310, the second solder ribbon 320 and the battery cell 100, reduce or avoid the phenomenon of solder ribbon 300 displacement, and improve safety.

[0055] Optionally, the adhesive 200 in this embodiment can be one of EVA, POE or PVB, thereby reducing the cost of the adhesive 200 and making it readily available.

[0056] Optionally, the volume resistivity of the adhesive component 200 is set to be greater than 10^13 Ω·cm. The adhesive component 200 is softened by being subjected to a temperature of 50℃-200℃ for a certain period of time and then bonded to the battery cell 100 or the solder ribbon 300.

[0057] Optionally, the adhesive 200 in this embodiment can be configured as a strip shape.

[0058] Optionally, in this embodiment, the thickness of the adhesive 200, the thickness of the first solder pad 1101, and the thickness of the second solder pad 1201 are equal. This ensures that the heights of the first solder ribbon 310 and the second solder ribbon 320 are as consistent as possible within a single battery cell, which is beneficial for subsequent lamination processes and prevents microcracks in the battery cell 100 during lamination, thus improving safety.

[0059] For example, the thickness of the adhesive 200, the thickness of the first pad 1101, and the thickness of the second pad 1201 in this embodiment can all be set to between 50μm and 150μm.

[0060] like Figures 1-2 As shown, in this embodiment, multiple first pads 1101 are equally spaced, and multiple second pads 1201 are equally spaced; the width of the adhesive 200 is no greater than the distance between two adjacent first pads 1101, and the width of the adhesive 200 is no greater than the distance between two adjacent second pads 1201. This ensures the bonding stability between the adhesive 200 and the first solder ribbon 310 and the second solder ribbon 320, while preventing the adhesive 200 from obstructing the first pads 1101 and the second pads 1201. This ensures the welding performance of the first solder ribbon 310 to the first pad 1101, and the welding performance of the second solder ribbon 320 to the second pad 1201, avoiding poor welding phenomena such as cold solder joints.

[0061] Furthermore, in this embodiment, the first pad 1101 and the second pad 1201 are at the same height along the second direction. This facilitates the setting of the adhesive 200. Only one strip of adhesive 200 needs to be set at the same height (i.e., along the first direction), eliminating the need to cut the adhesive 200 and improving work efficiency.

[0062] like Figures 1-2 As shown, along the second direction, the length of the adhesive 200 is not less than the distance between two adjacent first solder strips 310, and / or, along the second direction, the length of the adhesive 200 is not less than the distance between two adjacent second solder strips 320. This enables the adhesive 200 to achieve a fixed connection between the two adjacent first solder strips 310 (or the two adjacent second solder strips 320) and the battery cell 100, preventing the first solder strips 310 and the second solder strips 320 from shifting.

[0063] Optionally, the battery cell 100 in this embodiment is a back contact battery, i.e., a BC (Back Contact) battery.

[0064] like Figures 3-5 As shown, this embodiment also provides a battery string, which includes at least two of the aforementioned battery cells. The edges of the two battery cells partially overlap, wherein the front side of one battery cell is connected to the adhesive 200 on the back side of an adjacent battery cell. A first solder strip 310 in one battery cell is soldered to a second electrode 120 in an adjacent battery cell, and a second solder strip 320 in one battery cell is soldered to a first electrode 110 in an adjacent battery cell, so that adjacent battery cells are connected in series.

[0065] By partially overlapping the edges of two battery cells, more battery cells can be arranged in a battery string of a certain length, thereby increasing the power generation of photovoltaic modules and achieving the goal of reducing costs and increasing efficiency.

[0066] Optionally, in this embodiment, the edges of two adjacent battery cells are partially overlapped to form an overlapping portion, the width of which does not exceed 2mm.

[0067] like Figure 3 As shown, a first busbar 400 and a second busbar 500 are respectively provided at both ends of the battery string. The first busbar 400 is connected to the first solder strip 310 on the first battery cell in the battery string, and the second busbar 500 is connected to the second solder strip 320 on the last battery cell in the battery string. The arrangement of the first busbar 400 and the second busbar 500 enables the current in the battery string to be discharged.

[0068] Because the battery string has the aforementioned battery cells, it can reduce the occurrence of solder ribbon 300 misalignment, improve the stability and reliability of the connection between solder ribbon 300 and battery cell 100, enhance safety, and save costs.

[0069] This embodiment also provides a method for preparing a battery string, which includes the following steps:

[0070] The first solar cell 100 is transported to the work platform with its back side facing up. The adhesive 200 is then softened and fixed to the back side of the solar cell 100 by heating, ensuring that the adhesive 200 is positioned between two adjacent first pads 1101 of the same first electrode 110 and between two adjacent second pads 1201 of the same second electrode 120. The adhesive 200 is also placed at the edge of the solar cell 100. Solder ribbon 300 is then placed onto the same electrode of the first solar cell 100, and the next solar cell 100 is stacked on top of it at the edge of the first solar cell 100, with an overlap width not exceeding 2 mm. The adhesive 200 is then attached to the second solar cell 100 using the same method, and solder ribbon 300 is placed on different electrodes in the same direction on both solar cells 100. The two solar cells 100 are interconnected by heating. When the heating temperature reaches the melting point of the surface alloy of the solder ribbon 300, the solder ribbon 300 simultaneously forms a welding effect with the first solder pad 1101 and the second solder pad 1201 on the solar cell 100, and at the same time, the solder ribbon 300 can be bonded to the adhesive component 200. A minimum temperature is preferred to reduce warping of the solar cell 100 caused by the difference in thermal expansion and contraction between the solder ribbon 300 and the solar cell 100. This process is repeated until multiple solar cells 100 are interconnected to form a battery string.

[0071] In one optional embodiment, the method for preparing the battery string includes the following steps:

[0072] All the solar cells 100 are transported to the work platform with their backs facing up. The adhesive 200 is then softened and fixed to the back of the solar cells 100 by heating, ensuring that the adhesive 200 is positioned between two adjacent first pads 1101 of the same first electrode 110 and between two adjacent second pads 1201 of the same second electrode 120. Adhesive 200 is also placed at the edges of the solar cells 100. Adjacent solar cells 100 are stacked sequentially, with an overlap width not exceeding 2 mm. Solder ribbons 300 are then placed on the same electrode of each solar cell 100 and on different electrodes of adjacent solar cells 100. Heating is used to bond the solder ribbons 300 to the adhesive 200. When the heating temperature reaches the melting point of the surface alloy of the solder ribbons 300, the solder ribbons 300 simultaneously weld to the first pads 1101 and second pads 1201 on the solar cells 100, forming a solar cell string.

[0073] Obviously, the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the protection scope of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments. Many other equivalent embodiments may be included without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

[0074] Note that in the description of this specification, the references to terms such as "some embodiments," "other embodiments," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this utility model. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

Claims

1. A battery cell, characterized in that, include: A battery cell (100) has a plurality of first electrodes (110) and a plurality of second electrodes (120) disposed on one side. The first electrodes (110) and the second electrodes (120) both extend along a first direction. The plurality of first electrodes (110) are spaced apart, and the plurality of second electrodes (120) are spaced apart. The first electrodes (110) and the second electrodes (120) are arranged alternately along a second direction. The first direction and the second direction are perpendicular to each other. The first electrode (110) includes a plurality of first pads (1101), and the second electrode (120) includes a plurality of second pads (1201); An adhesive (200) is bonded to the battery cell (100) along the second direction. The adhesive (200) is located on the same side of the battery cell (100) as the first electrode (110) and the second electrode (120). The adhesive (200) is located between two adjacent first pads (1101) in the same first electrode (110) and between two adjacent second pads (1201) in the same second electrode (120). And / or, the adhesive (200) is located at the edge of the battery cell (100). The solder strip (300) includes a first solder strip (310) and a second solder strip (320). The first solder strip (310) is soldered to the first pad (1101), and the second solder strip (320) is soldered to the second pad (1201). Both the first solder strip (310) and the second solder strip (320) extend along the first direction. Both the first solder strip (310) and the second solder strip (320) are connected to the adhesive (200).

2. The battery cell according to claim 1, characterized in that, Multiple first pads (1101) are equally spaced, and multiple second pads (1201) are equally spaced; the width of the adhesive (200) is not greater than the distance between two adjacent first pads (1101), and the width of the adhesive (200) is not greater than the distance between two adjacent second pads (1201).

3. The battery cell according to claim 2, characterized in that, Along the second direction, the first pad (1101) and the second pad (1201) are at the same height.

4. The battery cell according to claim 1, characterized in that, Along the second direction, the length of the adhesive (200) is not less than the distance between two adjacent first weld strips (310); And / or, along the second direction, the length of the adhesive (200) is not less than the distance between two adjacent second weld strips (320).

5. The battery cell according to claim 1, characterized in that, The adhesive (200) is provided in a plurality of positions, and the plurality of adhesives (200) are arranged at equal intervals along the first direction, and / or the plurality of adhesives (200) are arranged at equal intervals along the second direction.

6. The battery cell according to claim 1, characterized in that, The adhesive component (200) is one of EVA, POE, or PVB.

7. The battery cell according to claim 1, characterized in that, The thickness of the adhesive (200), the thickness of the first pad (1101), and the thickness of the second pad (1201) are all equal.

8. The battery cell according to any one of claims 1-7, characterized in that, The battery cell (100) is a back contact battery.

9. A battery string, characterized in that, The battery string includes at least two battery cells according to any one of claims 1-8, with the edges of the two battery cells partially overlapping, wherein the front of one battery cell is connected to an adhesive (200) on the back of the adjacent battery cell. A first solder strip (310) in one of the battery cells is soldered to a second electrode (120) in an adjacent battery cell, and a second solder strip (320) in one of the battery cells is soldered to a first electrode (110) in an adjacent battery cell, so that two adjacent battery cells are connected in series.

10. The battery string according to claim 9, characterized in that, The battery string is provided with a first busbar (400) and a second busbar (500) at both ends. The first busbar (400) is connected to the first solder strip (310) on the first battery cell in the battery string, and the second busbar (500) is connected to the second solder strip (320) on the last battery cell in the battery string.

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