A welding strip and a battery cell assembly

Abstract

The present invention discloses a welding strip, the cross section of which includes a base and a reflecting portion arranged above the base, the reflecting portion including a top edge, a first side edge and a second side edge, a first angle is formed between the first side edge and an extension line of the top edge, a second angle is formed between the second side edge and an extension line of the top edge, and both the first angle and the second angle are greater than 42.5°. Compared with the prior art, the present invention forms a reflecting portion having a first side edge and a second side edge on the welding strip, and both the first angle and the second angle are acute angles greater than 42.5°. After sunlight irradiates the first side edge and the second side edge of the reflecting portion, reflected light is formed. The reflected light on the welding strip will be totally reflected at the glass-air interface layer of the photovoltaic module, so that the totally reflected sunlight re-participates in the photoelectric conversion, thereby improving the utilization rate of the reflected light.

Description

Technical Field

[0001] The invention relates to the technical field of photovoltaic welding strips, in particular to a welding strip and a battery cell assembly. Background Art

[0002] The welding ribbon, also known as the interconnection ribbon or the busbar ribbon, is an important raw material in the welding process of photovoltaic modules. The welding ribbon is usually used to connect the cells to each other and collect current by welding or conductive adhesive bonding. The quality of the welding ribbon will directly affect the current collection efficiency of the photovoltaic module and have a considerable impact on the power of the photovoltaic module. The cross-section of the existing conventional welding ribbon is mostly rectangular, circular, and a very small number of triangular.

[0003] The cross-section of the solder strip is rectangular. Most of the incident light beams that hit the surface of the rectangular solder strip at different angles are directly reflected to the glass above rather than the surface of the battery cell below. This is a reflected light loss.

[0004] The cross section of the welding ribbon is circular. Most of the incident light beams that hit the surface of the circular welding ribbon at different angles are scattered in multiple directions. Only a small part of the reflected light directly reaches the surface of the solar cell, that is, the utilization rate of reflected light is very low. As the diameter of the circular welding ribbon increases, a welding ribbon shadow will appear on the opposite side of the incident light, resulting in less power generation under low irradiation conditions. In addition, the contact surface with the solar cell during welding is relatively small, and the long-term reliability of welding is more risky than that of conventional rectangular welding ribbons. Summary of the invention

[0005] The object of the present invention is to provide a welding strip and a battery cell assembly to solve the technical problems in the prior art.

[0006] The present invention provides a welding strip, the cross-section of which includes a base and a reflecting portion arranged above the base, the reflecting portion includes a top edge, a first side edge and a second side edge, one end of the first side edge and the second side edge are connected to the top edge, the other end of the first side edge and the second side edge are connected to the base, a first angle is formed between the first side edge and the extension line of the top edge, a second angle is formed between the second side edge and the extension line of the top edge, and both the first angle and the second angle are acute angles greater than 42.5°.

[0007] In the welding strip as described above, preferably, the first angle and the second angle are both between 60° and 70°.

[0008] A welding strip as described above, wherein preferably, the first side edge and / or the second side edge comprises a plurality of continuous folded edge segments, and the angles between the plurality of folded edge segments and the extension lines of the top edge are all acute angles greater than 42.5°.

[0009] The welding strip as described above, wherein preferably, the cross-sectional height of the welding strip is 60-80% of the cross-sectional width.

[0010] A welding strip as described above, wherein preferably, the cross-sectional height of the welding strip does not exceed 0.3 mm.

[0011] In the welding strip as described above, preferably, the width of the base is 0.4±0.1 mm, and the height is 0.18±0.02 mm; and the height of the reflecting portion is 0.09±0.01 mm.

[0012] In the soldering strip as described above, preferably, the base has a width of 0.41 mm and a height of 0.2 mm or a width of 0.4 mm and a height of 0.17 mm; and the height of the reflecting portion is 0.1 mm.

[0013] A welding strip as described above, wherein preferably, the base comprises a bottom edge, a third side edge and a fourth side edge, the third side edge and the fourth side edge are arranged opposite to each other, wherein:

[0014] Two opposite ends of the third side are respectively connected to the bottom side and the first side, and a third angle is formed between the third side and the bottom side;

[0015] Two opposite ends of the fourth side are respectively connected to the bottom side and the second side, and an angle between the fourth side and the bottom side forms a fourth angle.

[0016] In the welding strip as described above, preferably, the third angle and the fourth angle are both between 90° and 120°.

[0017] In the welding strip as described above, preferably, the third angle and / or the fourth angle are acute angles.

[0018] A solder strip as described above, wherein preferably, the solder strip comprises a copper substrate and a solder layer wrapped around the surface of the copper substrate; the material of the copper substrate is pure copper, oxygen-free copper or red copper, and the material of the solder layer is pure tin, a tin-lead mixture or a tin-lead-silver mixture.

[0019] In the soldering strip as described above, preferably, the solder layer has a thickness of 10-15 μm.

[0020] The present invention also provides a battery cell assembly, which includes a backplane, encapsulation glass and battery cells, adjacent battery cells are electrically connected via welding strips, the backplane is arranged below the battery cells, the encapsulation glass is located above the battery cells, an encapsulation film is filled between the backplane and the battery cells, and between the encapsulation glass and the battery cells, the welding strip includes a main section, the cross-section of the main section includes a base and a reflecting portion arranged above the base, the reflecting portion includes a top edge, a fifth side edge and a sixth side edge, the fifth side edge and the sixth side edge are both convex arc structures, one end of the fifth side edge and the sixth side edge is connected to the top edge, and the other end of the fifth side edge and the sixth side edge is connected to the base, a fifth angle is formed between the tangent of the midpoint of the fifth side edge and the extension line of the bottom edge of the base, a sixth angle is formed between the tangent of the midpoint of the sixth side edge and the extension line of the bottom edge of the base, and the fifth angle and the sixth angle are both acute angles greater than 42.5°.

[0021] A battery cell assembly as described above, wherein preferably, the welding strip further includes a flat section, the flat section is connected to the main section, the main section is welded to the main grid line of the battery cell, and the flat section is located between two of the battery cells.

[0022] In the battery cell assembly as described above, preferably, the flat section is a flat, narrow and long structure, and the bottom edge of the flat section is parallel to the bottom edge of the base.

[0023] In the battery cell assembly as described above, preferably, the first angle and the second angle are both between 60° and 70°.

[0024] In the battery cell assembly as described above, preferably, the cross-sectional height of the welding strip is 60-80% of the cross-sectional width.

[0025] In the battery cell assembly as described above, preferably, the cross-sectional height of the welding strip does not exceed 0.3 mm.

[0026] In the battery cell assembly as described above, preferably, the width of the base is 0.4±0.1 mm, and the height is 0.18±0.02 mm; and the height of the reflective portion is 0.09±0.01 mm.

[0027] In the battery cell assembly as described above, preferably, the base has a width of 0.41 mm and a height of 0.2 mm or a width of 0.4 mm and a height of 0.17 mm; and the height of the reflective portion is 0.1 mm.

[0028] A battery cell assembly as described above, wherein preferably, the base also includes a seventh side and an eighth side, and the seventh side and the eighth side are arranged opposite to each other, wherein: the opposite ends of the seventh side are respectively connected to the bottom edge and the fifth side, and the opposite ends of the eighth side are respectively connected to the bottom edge and the sixth side, and an arc transition is formed between the seventh side and the bottom edge, and between the eighth side and the bottom edge.

[0029] In the battery cell assembly as described above, preferably, a massing layer is formed between the base and the battery cell, and the massing layer is formed by melting and depositing the solder layer.

[0030] Compared with the prior art, the present invention forms a reflecting portion having a first side edge and a second side edge on the welding strip, and the first angle and the second angle are both acute angles greater than 42.5°. After the sunlight is irradiated onto the first side edge and the second side edge of the reflecting portion, reflected light is formed. The reflected light on the welding strip will be totally reflected at the interface layer between the glass and the air of the photovoltaic module, so that the totally reflected sunlight can re-participate in the photoelectric conversion, thereby improving the utilization rate of the reflected light. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a schematic structural diagram of Embodiment 1 of the present invention;

[0032] Figure 2 is an axonometric view of the first embodiment of the present invention;

[0033] Figure 3 It is a structural schematic diagram of a size of the first embodiment of the present invention;

[0034] Figure 4 is a structural schematic diagram of another size of the first embodiment of the present invention;

[0035] Figure 5 is a schematic diagram of the structure of the welding strip reflecting light according to the first embodiment of the present invention;

[0036] Figure 6 is a schematic structural diagram of Embodiment 2 of the present invention;

[0037] Figure 7 is a schematic diagram of the structure of the welding strip reflecting light in the second embodiment of the present invention;

[0038] Figure 8 It is a schematic diagram of the structure of a battery cell assembly;

[0039] Fig. 9 It is a top view of the battery cell assembly.

[0040] Fig.10 It is a schematic diagram of the structure of the welding strip of the battery cell assembly;

[0041] Fig.11 It is a schematic diagram of the agglomerated structure of the bevel solder layer after the triangular solder strip is welded in the prior art;

[0042] Fig.12 It is a schematic diagram of the agglomerated structure of the solder layer of the solder strip of the battery cell assembly of the present invention.

[0043] Explanation of the accompanying drawings: 1-base, 2-reflecting part, 3-top edge, 4-first side edge, 5-second side edge, 6-first angle, 7-second angle, 8-bottom edge, 9-third side edge, 10-fourth side edge, 11-third angle, 11-fourth angle, 12-back plate, 13-encapsulation glass, 14-battery cell, 15-encapsulation film, 16-soldering strip, 17-copper base, 18-solder layer, 19-folded edge section, 20-fifth side edge, 21-sixth side edge, 22-seventh side edge, 23-eighth side edge, 24-fifth angle, 25-sixth angle. DETAILED DESCRIPTION

[0044] The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, but should not be construed as limiting the present invention.

[0045] Embodiment 1

[0046] like Figure 1 and Figure 2 As shown, an embodiment of the present invention provides a welding strip 16, which is a long strip structure. The cross-section of the welding strip 16 includes a base 1 and a reflecting part 2 arranged above the base 1. The reflecting part 2 and the base 1 are preferably an integral structure, and are divided into two parts only for functional description. The reflecting part 2 includes a top edge 3, a first side edge 4 and a second side edge 5. One end of the first side edge 4 and the second side edge 5 are connected to the top edge 3, and the other end of the first side edge 4 and the second side edge 5 are connected to the base 1. A first angle 6 is formed between the first side edge 4 and the extension line of the bottom edge 8 of the base 1, and a second angle 7 is formed between the second side edge 5 and the extension line of the bottom edge 8 of the base. The first angle 6 and the second angle 7 are both greater than 42.5° and less than 90° (excluding 90°).

[0047] In this embodiment, when the first angle 6 and / or the second angle 7 is greater than 42.5° and less than 90°, refer to Figure 5As shown, after the reflected light on the solder strip 16 perpendicular to the second side 5 irradiates the encapsulation glass 13, its incident angle (the angle between the reflected light and the normal of the encapsulation glass 13) is equal to the second angle 7. According to the principle of total reflection of light, the reflected light on the solder strip 16 will be totally reflected at the interface layer between the glass and the air of the battery cell assembly, so that the totally reflected sunlight will re-participate in the photoelectric conversion to improve the utilization rate of the reflected light.

[0048] Preferably, when the first angle 6 and the second angle 7 are greater than 42.5°, 42.5° is the critical angle for total reflection of sunlight at the glass-air interface layer of the photovoltaic cell assembly. When the first angle 6 and the second angle 7 are equal to or greater than this critical angle, the reflected light of the welding ribbon 16 will be totally reflected back to the cell 14 to participate in photoelectric conversion. If the first angle 6 and the second angle 7 are less than this angle, the reflected light of the welding ribbon 16 cannot meet the requirement of total reflection and will pass through the encapsulation glass 13 of the cell assembly, thus failing to be utilized.

[0049] Furthermore, the values ​​of the first angle 6 and the second angle 7 are equal, that is, the first side 4 and the second side 5 are symmetrically arranged about the perpendicular bisector of the bottom edge 8 of the base 1. The structure is symmetrically distributed, which is convenient for processing and molding, and can evenly reflect sunlight to the battery cells 14 on both sides, thereby improving the reflection efficiency.

[0050] Furthermore, the first angle 6 and the second angle 7 are both between 60° and 70°. In this way, on the one hand, the first angle 6 and the second angle 7 can be greater than the critical angle for total reflection of sunlight at the glass and air interface layer of the photovoltaic cell assembly. On the other hand, it also prevents the solder layer 18 from melting and causing accumulation during the welding process of the solder strip 16, thereby increasing the thickness of the first side 4 and the second side 5, thereby reducing the first angle 6 and the second angle 7. Setting the first angle 6 and the second angle 7 to 60°-70° can leave a margin, so that when the solder layer 18 accumulates, the first angle 6 and the second angle 7 are still greater than the critical angle for total reflection of sunlight at the glass and air interface layer of the battery cell assembly.

[0051] Furthermore, the cross-sectional height of the welding ribbon 16 is less than 0.3 mm. With this design, under the same copper substrate 17 as the round wire welding ribbon 16 (i.e., maintaining the same power), the height of the welding ribbon 16 is reduced, so the weight of the packaging film 15 can be reduced, thereby reducing the cost. After the welding ribbon 16 is welded to the battery cell 14, the packaging film 15 will be filled between the battery cell 14 and the packaging glass 13, and the height of the welding ribbon 16 will determine the gap between the battery cell 14 and the packaging glass 13. When the height of the welding ribbon 16 is reduced, the gap between the battery cell 14 and the packaging glass 13 can also be reduced, thereby reducing the volume of the filled packaging film 15.

[0052] Furthermore, the width of the base 1 is 0.4±0.1mm, and the height is 0.18±0.02mm; the height of the reflector 2 is 0.09±0.01mm. Thus, the width of the welding strip 16 is expanded to a certain extent compared with the height, and it is not easy to turn over during the welding process, which solves the problem of difficulty in the welding process of the triangular welding strip in the prior art.

[0053] Reference Figure 3 As shown, taking the size of the welding strip 16 of 0.3mm high and 0.41mm wide as an example, it is compared with the round wire segmented welding wire of the same copper substrate 17:

[0054] 1. Cost:

[0055] Since the height of 0.3mm*0.41mm is 0.3mm, it can use lower-weight film packaging materials than the round wire 0.35mm solder strip, and the cost of a single film for the component can be reduced by 4-5 yuan.

[0056] 2. Power:

[0057] Taking the 182-72HC module as an example, the T-shaped 0.3mm*0.41mm solder strip 16 can increase the power by about 1W compared to the round wire 0.35mm module due to its reflective design.

[0058] Reference Figure 4 As shown, taking the size of the welding strip 16 of 0.28mm high and 0.4mm wide as an example, it is compared with the round wire segmented welding wire of the same copper substrate 17:

[0059] 1. Cost:

[0060] Since the height of 0.28mm*0.4mm is 0.17mm, a lower-weight adhesive film packaging material can be used than the round wire 0.35mm solder ribbon, and the cost of a single piece of adhesive film for the component can be reduced by 4.3-5.3 yuan.

[0061] 2. Power:

[0062] Taking the 182-72HC module as an example, the T-shaped 0.28mm*0.4mm solder strip 16 can increase the power by about 1W compared to the round wire 0.35mm module due to its reflective design.

[0063] In the prior art, Fig.11 As shown, the cross-section of the solder strip is a triangle. Although the design concept intends to provide two inclined edges as effective sides in order to increase the effective reflective reuse area, the solder layer on the inclined edges will melt and agglomerate in the middle of the inclined edges after welding, causing the two inclined edges of the solder strip to change from inclined surfaces to arc-shaped surfaces with a large protrusion in the middle after welding, similar to the surface of a round welding wire, resulting in a loss of reflective reuse capability.

[0064] In order to solve the above technical problems, the base 1 also includes a third side 9 and a fourth side 10, and the third side 9 and the fourth side 10 are arranged opposite to each other, wherein: the opposite ends of the third side 9 are respectively connected to the bottom side 8 and the first side 4, and a third angle 11 is formed between the third side 9 and the bottom side 8; the opposite ends of the fourth side 10 are respectively connected to the bottom side 8 and the second side 5, and the angle between the fourth side 10 and the bottom side 8 forms a fourth angle 12. The third angle 11 and the fourth angle 12 are preferably right angles, so that a structure with an isosceles trapezoid on the top and a rectangle on the bottom can be formed, which meets the requirements of light reflection, and does not cause the solder layer 18 to agglomerate after bevel welding like the triangular welding strip 16. Fig.11 As shown, a massing layer is formed between the base 1 and the battery cell 14, the solder layer 18 slides to the bottom, and the solder layer 18 does not aggregate on the bevel, which has a good reflective effect.

[0065] Furthermore, the third angle 11 and the fourth angle 12 are both obtuse angles, preferably 120°, that is, the third side 9 and the fourth side 10 are gradually inclined inward from top to bottom to form a diamond-like structure. After welding, since the third side 9 and the fourth side 10 are inclined inward, relative to the rectangular structure design of the base, the third side 9 and the fourth side 10 respectively form a certain clearance space with the top of the battery cell 14, so the solder layer 18 slides from the first side 4 and the second side 5 to accumulate in the clearance space after welding, thereby reducing the obstruction of the surface of the battery cell 14.

[0066] The soldering strip 16 includes a copper substrate 17 and a solder layer 18 wrapped on the surface of the copper substrate 17; the copper substrate 17 is made of pure copper, oxygen-free copper or red copper, and the solder layer 18 is made of pure tin, a tin-lead mixture or a tin-lead-silver mixture. The copper substrate 17 is used for current transmission, and the solder layer 18 is used for welding with the grid line on the surface of the battery cell 14. The thickness of the solder layer 18 is controlled to be 10-15 μm and is evenly wrapped on the copper substrate 17.

[0067] Embodiment 2

[0068] The main difference between this embodiment and the first embodiment is that in the first embodiment, the first side edge 4 and / or the second side edge 5 is a nearly smooth surface, the reflected light angle generated by it is single and the coverage range is not wide, while in this embodiment, the first side edge 4 and / or the second side edge 5 is a nearly smooth surface, the reflected light angle generated by it is single and the coverage range is not wide. Figure 6 and Figure 7 As shown, the first side edge 4 and / or the second side edge 5 include a plurality of continuous folded edge segments 19, and the angles between the plurality of folded edge segments 19 and the extension lines of the bottom edge 8 of the base 1 are all greater than the preset angle. In this way, the angle of sunlight reflected by each folded edge segment 19 is different, thereby increasing the coverage of sunlight that re-participates in photoelectric conversion.

[0069] Reference Figure 7 As shown, after the reflected light on the welding ribbon 16 perpendicular to the folded edge section 19 irradiates the packaging glass 13, the incident angle (the angle between the reflected light and the normal of the packaging glass 13) is equal to the second angle 7. According to the principle of total reflection of light, the reflected light on the welding ribbon 16 will be totally reflected at the interface layer between the glass and the air of the battery cell assembly, so that the totally reflected sunlight will re-participate in the photoelectric conversion to improve the utilization rate of the reflected light.

[0070] Furthermore, the angle between the folded edge section 19 and the extension line of the bottom edge 8 of the base 1 increases from top to bottom, forming a gradient gradually inclined surface, so that the welding layer can slide down along the folded edge sections 19 during the melting process, and will not agglomerate on the first side edge 4 and / or the second side edge 5, affecting the reflective effect and reducing the utilization rate of sunlight.

[0071] The present invention also provides a battery cell assembly, referring to Figure 8 and Fig. 9 As shown, the cell assembly includes a cell 14 and the aforementioned welding ribbon 16, and the base 1 of the welding ribbon 16 is welded to the cell 14. Adjacent cells 14 are electrically connected to each other through the welding ribbon 16, and the welding ribbon 16 is used to transmit current.

[0072] Reference Fig.10As shown, the cross section of the solder strip 16 includes a base 1 and a reflective portion 2 disposed above the base 1, the reflective portion 2 includes a top edge 3, a fifth side edge 20 and a sixth side edge 21. During the soldering process of the solder strip 16, the solder of its solder layer 18 (especially at a position close to the soldering point) melts, resulting in a certain amount of flow accumulation, resulting in the fifth side edge 20 and the sixth side edge 21 being both slightly convex arc structures, and the top edge 3 can also be an arc structure, which connects the fifth side edge 20 and the sixth side edge 21, and the fifth side edge 20 and the sixth side edge 21 are connected to each other. One end of the fifth side 20 and the sixth side 21 are connected to the base 1, and the other ends of the fifth side 20 and the sixth side 21 are connected to the base 1. A fifth angle 24 is formed between the tangent of the fifth side 20 and the extension line of the bottom edge of the base 1, and a sixth angle 25 is formed between the tangent of the sixth side 21 and the extension line of the bottom edge of the base 1. The tangents of the fifth side 20 and the sixth side 21 are both tangents of the farthest point of the convex arc surface, and the fifth angle 24 and the sixth angle 25 are both between 42.5° and 90° (excluding 90°).

[0073] After the soldering of the soldering ribbon 16, the solder layer 18 melts, and the fifth side 20 and the sixth side 21 form an outwardly convex arc structure. The angle between the midpoint tangent of the fifth side 20 and the sixth side 21 and the extension line of the bottom edge 8 of the base 1 is greater than 42.5°. The position of the midpoint of the fifth side 20 and the sixth side 21 is the most prominent point of the arc structure. Preferably, this midpoint is in the middle of the arc structure. After the reflected light on the soldering ribbon 16, which is perpendicular to the fifth side 20 and the sixth side 21, is irradiated onto the encapsulating glass 13, its incident angle (the angle between the reflected light and the normal of the encapsulating glass 13) is equal to the fifth angle 24 and the sixth angle 25. According to the principle of total reflection of light, the reflected light on the soldering ribbon 16 will be totally reflected at the glass-air interface layer of the battery cell assembly, so that the totally reflected sunlight will re-participate in the photoelectric conversion to improve the utilization rate of the reflected light.

[0074] Furthermore, the welding strip 16 includes a main section and a flat section. The main section is used to weld to the main grid line of the battery cell 14, and the flat section is located between two adjacent battery cells 14, eliminating the spacing between cells and increasing the power of the component per unit area; the middle flat section reduces the upper and lower spacing between the battery cells 14, reduces the amount of EVA used, reduces hidden cracks, and improves the reliability of the photovoltaic component.

[0075] Furthermore, the flat section is a flat and elongated structure, and the bottom edge of the flat section is parallel to the bottom edge of the base, thereby preventing the welding strip from being reversed during the welding process.

[0076] The cell assembly further includes an encapsulation glass 13 and a back plate 12 . The back plate 12 is disposed below the cell 14 . The encapsulation glass 13 is located above the cell 14 . An encapsulation film 15 is filled between the encapsulation glass 13 and the cell 14 .

[0077] Furthermore, the base 1 also includes a seventh side 22 and an eighth side 23, and the seventh side 22 and the eighth side 23 are arranged opposite to each other, wherein: the opposite ends of the seventh side 22 are respectively connected to the bottom edge 8 and the fifth side 20, and the opposite ends of the eighth side 23 are respectively connected to the bottom edge 8 and the sixth side 21, and an arc transition is formed between the seventh side 22 and the bottom edge 8, and between the eighth side 23 and the bottom edge 8.

[0078] Since arc transitions are formed between the seventh side 22 and the bottom edge 8 and between the eighth side 23 and the bottom edge 8, relative to the rectangular base, it is equivalent to adding a rounded corner design, which is beneficial to the accumulation of the solder layer 18 at the bottom of the solder strip 16 and helps to reduce collision damage to the battery cell 14.

[0079] Furthermore, the fifth angle 24 and the sixth angle 25 are both between 60° and 70°. In this way, on the one hand, the fifth angle 24 and the sixth angle 25 can be greater than the critical angle for total reflection of sunlight at the glass and air interface layer of the photovoltaic cell assembly. On the other hand, it also prevents the solder layer 18 from melting and causing accumulation during the welding process of the solder strip 16, thereby increasing the thickness of the fifth side 20 and the sixth side 21, thereby reducing the fifth angle 24 and the sixth angle 25. Setting the fifth angle 24 and the sixth angle 25 to 60°-70° can leave a margin, so that when the solder layer 18 accumulates, the fifth angle 24 and the sixth angle 25 are still greater than the critical angle for total reflection of sunlight at the glass and air interface layer of the battery cell assembly.

[0080] Furthermore, the cross-sectional height of the welding ribbon 16 is less than 0.3 mm. With this design, under the same copper substrate 17 as the round wire welding ribbon 16 (i.e., maintaining the same power), the height of the welding ribbon 16 is reduced, so the weight of the packaging film 15 can be reduced, thereby reducing the cost. After the welding ribbon 16 is welded to the battery cell 14, the packaging film 15 will be filled between the battery cell 14 and the packaging glass 13, and the height of the welding ribbon 16 will determine the gap between the battery cell 14 and the packaging glass 13. When the height of the welding ribbon 16 is reduced, the gap between the battery cell 14 and the packaging glass 13 can also be reduced, thereby reducing the volume of the filled packaging film 15.

[0081] Furthermore, the width of the base 1 is 0.4±0.1mm, and the height is 0.18±0.02mm; the height of the reflector 2 is 0.09±0.01mm. As a result, the width of the welding strip 16 is expanded to a certain extent compared with the height, and it is not easy to turn over during the welding process, which solves the problem of difficulty in the welding process of the triangular welding strip in the prior art. After the welding strip 16 is welded, Fig.12 As shown, a clustering layer is formed between the base 1 and the battery cell 14, the solder layer 18 slides to the bottom, and the solder layer 18 is not clustered on the oblique side of the trapezoidal structure of the solder strip 16. The solder layer 18 of the solder strip 16 is only clustered at the bottom of the base 1, which has a good reflective effect.

[0082] The above describes in detail the structure, features and effects of the present invention based on the embodiments shown in the drawings. The above is only a preferred embodiment of the present invention, but the present invention is not limited to the scope of implementation shown in the drawings. Any changes made according to the concept of the present invention, or modifications to equivalent embodiments with equivalent changes, which still do not exceed the spirit covered by the description and drawings, should be within the protection scope of the present invention.

Claims

1. A welding strip, characterized in that: The cross section of the welding strip includes a base and a reflecting portion provided above the base, the reflecting portion includes a top edge, a first side edge and a second side edge, one end of the first side edge and the second side edge is connected to the top edge, the other end of the first side edge and the second side edge is connected to the base, a first angle is formed between the first side edge and an extension line of the bottom edge of the base, a second angle is formed between the second side edge and an extension line of the bottom edge of the base, and both the first angle and the second angle are acute angles greater than 42.5°; The cross-sectional height of the welding strip does not exceed 0.3 mm; The width of the base is 0.4±0.1mm, and the height is 0.18±0.02mm; the height of the reflective portion is 0.09±0.01mm; The first side edge and / or the second side edge comprises a plurality of continuous folded edge segments, and the angles between the plurality of folded edge segments and the extension lines of the bottom edge of the base are all acute angles greater than 42.5°; The angle between the folded edge section and the extension line of the bottom edge of the base increases from top to bottom, forming a gradient gradually inclined surface; The base also includes a third side and a fourth side, and the third side and the fourth side are arranged opposite to each other, wherein: Two opposite ends of the third side are respectively connected to the bottom side and the first side, and a third angle is formed between the third side and the bottom side; Two opposite ends of the fourth side are respectively connected to the bottom side and the second side, and an angle between the fourth side and the bottom side forms a fourth angle; The third angle and the fourth angle are both obtuse angles.

2. The welding strip according to claim 1, characterized in that: The first angle and the second angle are both between 60° and 70°.

3. The welding strip according to claim 1, characterized in that: The cross-sectional height of the welding strip is 60-80% of the cross-sectional width.

4. The welding strip according to claim 1, characterized in that: The base has a width of 0.41 mm and a height of 0.2 mm or a width of 0.4 mm and a height of 0.17 mm; the height of the reflective portion is 0.1 mm.

5. The welding strip according to claim 1, characterized in that: The solder strip includes a copper substrate and a solder layer wrapped on the surface of the copper substrate; the material of the copper substrate is pure copper, oxygen-free copper or red copper, and the material of the solder layer is pure tin, tin-lead mixture or tin-lead-silver mixture.

6. The welding strip according to claim 5, characterized in that: The thickness of the solder layer is 10-15 μm.

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