Ejector pin module and welding equipment

Abstract

The utility model discloses an ejector pin module and welding equipment, the ejector pin module comprises at least one first ejector pin, the first ejector pin comprises a first ejector pin main body and a first ejector pin head connected with the first ejector pin main body, and the first ejector pin head is provided with a first jacking surface far away from the first ejector pin main body; when the first ejector pin abuts against the welding strip to the battery piece, the length direction of the first abutting face is parallel to the extending direction of the welding strip, and the orthographic projection of the first abutting face on the battery piece at least covers the two bonding pads. According to the embodiment of the utility model, the contact area between the first ejector pin and the welding strip is increased, so that the close contact area between the welding strip and the bonding pad is increased, pseudo soldering caused by poor contact between the bonding pad and the welding strip is avoided, the pseudo soldering rate and the pseudo overlapping condition are reduced, and the process yield is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of battery cell welding, in particular to an ejector pin module and welding equipment. Background Art

[0002] In the back contact cell, both the positive and negative electrodes are located on the back. After the back contact cell is prepared, multiple back contact cells need to be welded into a cell string through welding ribbons.

[0003] At present, the welding method of the welding ribbon and the battery cell is usually infrared welding. During the infrared welding process, the ejector pin presses the welding ribbon to make the welding ribbon and the pad on the back of the battery cell closely contact, so as to weld them together. Among them, multiple ejector pins correspond to multiple pads on the battery cell one by one.

[0004] However, due to the limitation of spatial arrangement, the number of ejector pins is limited and cannot meet the welding requirements of multi-pad battery cells, such as battery cells without main grid back contact. During the welding process, some pads have poor contact with the welding ribbon, which can easily cause cold solder joints, thus affecting the process yield. Utility Model Content

[0005] The utility model provides an ejector pin module and welding equipment, aiming at least to solve the technical problem in the prior art that cold solder joints are easily generated between battery cells and welding strips during welding, thereby affecting the process yield.

[0006] In a first aspect, an embodiment of the utility model provides an ejector pin module, comprising at least one first ejector pin, wherein the first ejector pin comprises a first ejector pin body and a first ejector pin head connected to the first ejector pin body, wherein the first ejector pin head has a first ejection pressing surface away from the first ejector pin body;

[0007] When the first ejector pin pushes the solder strip onto the battery cell, the length direction of the first pressing surface is parallel to the extension direction of the solder strip, and the orthographic projection of the first pressing surface on the battery cell covers at least two solder pads.

[0008] In the embodiment of the utility model, when the first ejector pin presses the welding strip onto the battery cell, the orthographic projection of the first pressing surface on the battery cell covers at least two pads. This arrangement increases the contact area between the first ejector pin and the welding strip, thereby increasing the area of ​​close contact between the welding strip and the pad, avoiding cold solder joints caused by poor contact between the pad and the welding strip, reducing cold solder joint rate and false overlap, improving process yield, reducing series resistance, and improving the power and reliability of the battery cell after welding. In addition, by changing the shape of the first ejector pin head, one first ejector pin can correspond to at least two pads, without increasing the number of the first ejector pins themselves, and facilitating the arrangement of the first ejector pins.

[0009] Optionally, the length of the first pressing surface is greater than or equal to 2 mm and less than or equal to 10 mm.

[0010] When the length of the first pressing surface is within the above range, the orthographic projection of the first pressing surface on the battery cell can cover more pads. At the same time, the first ejector pin is not easily deformed, thereby avoiding the deterioration of the welding effect caused by the deformation of the first ejector pin.

[0011] Optionally, a first groove is provided on the first pressing surface, the first groove passes through the first ejector pin head along the length direction of the first ejector pin head, and the width of the first groove is less than or equal to half the width or half the diameter of the welding strip.

[0012] The first groove is provided to prevent tin from blasting during welding and tin from overflowing to both sides of the welding strip, thereby avoiding process risks such as short circuits caused by tin blasting and tin overflowing to both sides of the welding strip.

[0013] Optionally, the width of the first pressing surface is greater than the width or diameter of the welding strip.

[0014] Through the above arrangement, it can be ensured that the welding strip is in full contact with the welding pad on the battery cell along the width direction of the welding strip, thereby ensuring the welding effect.

[0015] Optionally, a width of the first pressing surface is greater than or equal to 3 mm and less than or equal to 10 mm.

[0016] When the width of the first pressing surface is within the above range, it can be ensured that the width of the first pressing surface is greater than the width or diameter of the welding strip.

[0017] Optionally, the first pressing surface of the first ejector needle head is wavy in shape, and the first ejector needle head having a wavy first pressing surface has at least two crests and at least one trough, and the crests and the troughs are alternately arranged along the length direction of the first ejector needle head.

[0018] The trough acts as the first groove, which can prevent tin from exploding during the welding process and tin from overflowing to both sides of the welding strip, thereby avoiding process risks such as short circuits caused by tin exploding and tin overflowing to both sides of the welding strip.

[0019] Optionally, a plurality of the first ejector pins are arranged in an array to form a first ejector pin assembly, and the ejector pin module further comprises a plurality of second ejector pins located on both sides of the first ejector pin assembly along a first direction, and the first direction is parallel to a length direction of the first ejector pressing surface;

[0020] The second ejector pin includes a second ejector pin body and a second ejector pin head connected to the second ejector pin body, the second ejector pin head has a second pressing surface away from the second ejector pin body, and the area of ​​the second pressing surface is less than or equal to the area of ​​the first pressing surface.

[0021] The area of ​​the second pressing surface is sufficient to ensure close contact between the soldering ribbon and the edge soldering pad when the second ejector pin presses the soldering ribbon onto the battery cell, thereby reducing the cost of the second ejector pin.

[0022] Optionally, the first ejector pin is T-shaped, and the second ejector pin is inverted L-shaped.

[0023] Optionally, the second pressing surface is a circular plane or a rectangular plane;

[0024] When the second ejector pin presses the welding strip, and the second pressing surface is a rectangular plane, the length direction of the second pressing surface is parallel to the extending direction of the welding strip.

[0025] When the second pressing surface is a circular plane or a rectangular plane, the structure is simple and easy to manufacture.

[0026] Optionally, the first pressing surface is a rectangular plane, and when the second pressing surface is a rectangular plane, the width of the second pressing surface is greater than the width or diameter of the welding strip, and the length of the second pressing surface is less than or equal to the length of the first pressing surface.

[0027] When the width of the second top pressing surface is greater than the width or diameter of the welding ribbon, it can ensure that the welding ribbon is in full contact with the edge pad on the battery cell, thereby ensuring the welding effect.

[0028] Optionally, a plurality of the first ejector pins and two of the second ejector pins spaced apart and distributed along the first direction form an ejector pin group, and the sum of the number of the first ejector pins and the number of the second ejector pins in the ejector pin group is 5-10.

[0029] Optionally, the first ejector main body includes a first needle body connected to the first ejector head, and the number of the first needle bodies is one or two;

[0030] When the number of the first needle bodies is two, the two first needle bodies are arranged at intervals along the length direction of the first ejector needle head.

[0031] In a second aspect, an embodiment of the utility model provides a welding device, comprising the ejector pin module described in any one of the above items.

[0032] Optionally, the welding equipment is used for welding a battery cell to a welding ribbon, and the battery cell is a back contact battery cell and / or a busbarless battery cell.

[0033] The above description is only an overview of the technical solution of the utility model. In order to more clearly understand the technical means of the utility model, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the utility model more obvious and easy to understand, the specific implementation methods of the utility model are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 A schematic diagram of the structure of a first ejector pin in an ejector pin module provided in an embodiment of the utility model;

[0035] Figure 2 A schematic structural diagram of a first ejector pin head in an ejector pin module provided in an embodiment of the utility model;

[0036] Figure 3 A schematic diagram of the structure of the ejector module provided in an embodiment of the utility model;

[0037] Figure 4 A schematic structural diagram of a second ejector pin in an ejector pin module provided in an embodiment of the utility model;

[0038] Figure 5 A schematic diagram of the structure of another second ejector pin in the ejector pin module provided in an embodiment of the utility model;

[0039] Figure 6 A schematic diagram of the structure of a welding table in a welding device provided in an embodiment of the utility model;

[0040] Figure 7 A schematic diagram of the structure of a welding table and a heating adsorption device in a welding device provided in an embodiment of the utility model;

[0041] Figure 8 A schematic diagram of the structure of a battery cell that is welded by a welding device provided in an embodiment of the utility model;

[0042] Fig. 9 for Figure 8 Schematic diagram of the enlarged structure at point A in the middle.

[0043] Reference numerals:

[0044] 1-first ejector pin, 11-first ejector pin body, 111-first sleeve, 112-first needle body, 12-first ejector pin head, 121-first ejector pressure surface, 1211-first groove, 2-second ejector pin, 21-second ejector pin body, 22-second ejector pin head, 221-second ejector pressure surface, 3-ejector pin group, 4-welding table, 41-strip groove, 5-heating adsorption device, 51-heating element, 52-adsorption pressure pin, 6-battery cell, 61-fine grid line, 62-edge pad, 63-middle pad, 64-edge connecting grid line. DETAILED DESCRIPTION

[0045] The exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0046] At present, the welding method of the welding strip and the battery cell is usually infrared welding. During the infrared welding process, the ejector pin presses the welding strip to make the welding strip in close contact with the pad on the back of the battery cell, so as to weld them together. Among them, multiple ejector pins correspond one-to-one to multiple pads on the battery cell. For example, in a conventional back-contact battery cell, five to seven pads are arranged on the main grid line, and five to seven ejector pins correspond to the five to seven pads on the main grid line during the welding process. For a battery cell with multiple pads, such as a back-contact battery cell without a main grid, it has twenty to fifty pads in a direction perpendicular to the fine grid line. However, the conventional five to seven ejector pins corresponding to one welding strip cannot meet the welding requirements of a battery cell with multiple pads, and cold solder joints are easily generated during the welding process, thereby affecting the process yield. In order to solve the above problems, an embodiment of the utility model provides a ejector pin module and a welding device.

[0047] First, refer to Figures 1 to 3 The embodiment of the utility model discloses a ejector pin module, comprising at least one first ejector pin 1, wherein the first ejector pin 1 comprises a first ejector pin body 11 and a first ejector pin head 12 connected to the first ejector pin body 11, wherein the first ejector pin head 12 has a first pressing surface 121 away from the first ejector pin body 11; when the first ejector pin 1 presses the solder strip onto the battery cell 6, the length direction of the first pressing surface 121 is parallel to the extension direction of the solder strip, and the orthographic projection of the first pressing surface 121 on the battery cell 6 covers at least two solder pads.

[0048] Specifically, the ejector pin module is applied to welding equipment, and the welding equipment is used for welding the battery cell 6 to the welding strip. The first ejector pin 1 can be T-shaped. The first ejector pin body 11 is the main part of the first ejector pin 1, and the first ejector pin body 11 can include a first sleeve 111 and a first needle body 112, and the first needle body 112 is connected to the first sleeve 111 through a spring. The first needle body 112 is connected to the first ejector pin head 12, and the number of the first needle bodies 112 can be one, two, etc. When the number of the first needle bodies 112 is two, the two first needle bodies 112 are respectively connected to the two ends of the first ejector pin head 12 along its length direction to enhance the welding stability. The first ejector pin head 12 is used to press the welding strip so that the welding strip is in close contact with the pad on the battery cell 6.

[0049] The size of the battery cell 6 can be 166mm-210mm. The size of the battery cell 6 can be specifically 166mm, 182mm, 210mm, etc. The welding strip can be a flat welding strip, a round welding strip, a triangular welding strip, etc. The battery cell 6 can be divided into two halves. The fine grid line 61 can include anisotropic fine grid lines that are opposite in polarity to the welding strip and overlap with the positive projection of the welding strip on the battery cell. An insulating glue can be provided between the anisotropic fine grid lines and the welding strip to achieve insulation between the welding strip and the anisotropic fine grid lines.

[0050] The cell 6 may be a back contact cell and / or a busbar-free cell. The cell 6 is specifically an IBC (Interdigitated Back Contact) busbar-free cell. Figure 8 and Fig. 9 The cell 6 includes a plurality of fine grid lines 61, which include a plurality of positive fine grid lines and a plurality of negative fine grid lines, and the positive fine grid lines and the negative fine grid lines are arranged alternately. The cell 6 also includes array-distributed pads, which include a middle pad 63, and the width of the middle pad 63 can be 100 microns to 500 microns, and the length can be 100 microns to 10,000 microns.

[0051] The first pressing surface 121 may be a plane. Specifically, the first pressing surface 121 may be a rectangular plane, an irregular rectangular plane, a rectangular plane with chamfers, a waist-shaped plane, a dumbbell-shaped plane, etc., which are not limited here. The first pressing surface 121 is preferably a rectangular plane.

[0052] The first ejector pin 1 is specifically used to press the welding strip so that the welding strip is in close contact with the middle pad 63 on the battery cell 6, so that the two are welded together. When the first ejector pin 1 presses the welding strip onto the battery cell 6, the orthographic projection of the first pressing surface 121 on the battery cell 6 covers at least two middle pads 63. Preferably, when the first ejector pin 1 presses the welding strip onto the battery cell 6, the orthographic projection of the first pressing surface 121 on the battery cell 6 covers four or five middle pads 63. Two adjacent first ejector pins 1 may be spaced apart by two middle pads 63.

[0053] In the embodiment of the utility model, when the first ejector pin 1 presses the solder strip onto the battery cell 6, the orthographic projection of the first pressing surface 121 on the battery cell 6 covers at least two pads. This arrangement increases the contact area between the first ejector pin 1 and the solder strip, thereby increasing the area of ​​close contact between the solder strip and the pad, avoiding cold solder joints caused by poor contact between the pad and the solder strip, reducing cold solder joint rate and false overlap, improving process yield, reducing series resistance, and improving the power and reliability of the battery cell after welding. In addition, by changing the shape of the first ejector pin head 12, one first ejector pin 1 can correspond to at least two pads, without increasing the number of the first ejector pins themselves, and facilitating the arrangement of the first ejector pins.

[0054] In a preferred embodiment of the present invention, the length of the first pressing surface 121 is greater than or equal to 2 mm and less than or equal to 10 mm.

[0055] The length of the first pressing surface 121 can be 2mm, 5mm, 7mm, 8mm, 9mm, 10mm, etc. The length of the first pressing surface 121 is preferably 5mm-8mm. If the length of the first pressing surface 121 is too short, its orthographic projection on the battery cell 6 cannot cover more pads, thereby affecting the process yield. If the length of the first pressing surface 121 is too long, the first ejector pin 12 is prone to deformation during long-term use, and the welding effect will deteriorate. In the embodiment of the utility model, when the length of the first pressing surface 121 is within the above range, the orthographic projection of the first pressing surface 121 on the battery cell 6 can cover more pads. At the same time, the first ejector pin 12 is not easy to deform, thereby avoiding the deterioration of the welding effect caused by the deformation of the first ejector pin 12.

[0056] In a preferred embodiment of the present invention, referring to Figure 2 A first groove 1211 is formed on the first pressing surface 121 , and the first groove 1211 penetrates the first ejector pin 12 along the length direction of the first ejector pin 12 . The width of the first groove 1211 is less than or equal to half of the width or half of the diameter of the welding strip.

[0057] Specifically, the first groove 1211 can be a rectangular groove, a U-shaped groove, etc., and the depth of the first groove 1211 is less than the thickness of the first ejector head 12. The length direction and width direction of the first groove 1211 are respectively parallel to the length direction and width direction of the first ejector head 12. By setting the first groove 1211, it is possible to prevent tin from blasting during welding and tin from overflowing to both sides of the welding strip, thereby avoiding process risks such as short circuits caused by tin blasting and tin overflowing to both sides of the welding strip. In addition, by setting the width of the first groove 1211 to be less than or equal to half the width or half the diameter of the welding strip, it is possible to ensure that the first top pressure surface 121 is in contact with the welding strip.

[0058] In a preferred embodiment of the present invention, the width of the first top pressing surface 121 is greater than the width or diameter of the welding strip. When the width of the first top pressing surface 121 is greater than the width or diameter of the welding strip, it can ensure that the welding strip is in full contact with the pad on the battery cell 6 along the width direction of the welding strip, thereby ensuring the welding effect.

[0059] In a preferred embodiment of the present invention, the width of the first pressing surface 121 is greater than or equal to 3 mm and less than or equal to 10 mm.

[0060] The width of the first pressing surface 121 can be 3mm, 5mm, 6mm, 7mm, 8mm, 9mm, etc. The width or diameter of the welding strip is usually 2mm-8mm. When the width of the first pressing surface 121 is 3mm-10mm, it can be ensured that the width of the first pressing surface 121 is greater than the width or diameter of the welding strip.

[0061] In a preferred embodiment of the present invention, referring to Figures 3 to 5 A plurality of first ejector pins 1 are arranged in an array to form a first ejector pin assembly. The ejector pin module further includes a plurality of second ejector pins 2 located on both sides of the first ejector pin assembly along a first direction, and the first direction is parallel to the length direction of the first ejector surface 121; the second ejector pin 2 includes a second ejector pin body 21 and a second ejector pin head 22 connected to the second ejector pin body 21, and the second ejector pin head 22 has a second ejector surface 221 away from the second ejector pin body 21, and the area of ​​the second ejector surface 221 is less than or equal to the area of ​​the first ejector surface 121.

[0062] The first pressing surface 121 of the first ejector pin 12 is wavy in shape. The wavy first ejector pin 12 has at least two crests and at least one trough, and the crests and troughs are alternately arranged along the length direction of the first ejector pin 12 .

[0063] The trough acts as the first groove 1211, which can prevent tin from blasting and overflowing to both sides of the soldering strip during the welding process, thereby avoiding process risks such as short circuits caused by tin blasting and overflowing to both sides of the soldering strip. The trough is located between two adjacent peaks. The number of peaks can be 5-10 to ensure the uniformity of the top pressure of the first ejector pin 1. The number of troughs can be 5-10.

[0064] Specifically, the first direction can refer to Figure 3 The direction indicated by the arrow B in FIG. A plurality of first ejector pins 1 and two second ejector pins 2 spaced apart along the first direction form an ejector pin group 3, and one ejector pin group 3 is used to press a solder strip. The sum of the number of first ejector pins 1 and the number of second ejector pins 2 in one ejector pin group 3 is 5-10. The sum of the number of first ejector pins 1 and the number of second ejector pins 2 in one ejector pin group 3 can be 5, 6, 7, 8, 9, 10, etc. Figure 8 and Fig. 9 The pads also include edge pads 62 near the edges of both sides of the battery cell 6 along the second direction, and the second direction is perpendicular to the extension direction of the thin grid line 61. The size of the edge pads 62 is larger than that of the middle pads 63. The second ejector pin 2 is specifically used to push the welding strip so that the welding strip is in close contact with the edge pads 62 on the battery cell 6, so that the two are welded together.

[0065] The edge pad 62 may have a length of 100 microns to 10,000 microns and a width of 100 microns to 10,000 microns. The edge pad 62 is connected with an edge connection grid line 64, which is rectangular or trapezoidal, has a length of 1 mm to 10 mm and a width of 10 microns to 500 microns.

[0066] Since the second ejector pin 2 corresponds to an edge solder pad 62, the area of ​​the second pressing surface 221 can be designed to be less than or equal to the area of ​​the first pressing surface 121. The area of ​​the second pressing surface 221 is sufficient to ensure that the solder strip is in close contact with the edge solder pad 62 when the second ejector pin 2 presses the solder strip onto the battery cell, thereby reducing the cost of the second ejector pin 2.

[0067] In a preferred embodiment of the present invention, the second pressing surface 221 is a circular plane or a rectangular plane; when the second ejector pin 2 presses the welding strip and the second pressing surface 221 is a rectangular plane, the length direction of the second pressing surface 221 is parallel to the extension direction of the welding strip.

[0068] Specifically, when the second top pressing surface 221 is a rectangular plane, the second ejector pin 2 is an inverted L-shape. The second ejector pin body 21 may include a second sleeve and a second needle body, and the second needle body may be connected to the second sleeve via a spring. When the second top pressing surface 221 is a circular plane, the diameter of the second top pressing surface 221 is greater than the width or diameter of the welding strip. When the second top pressing surface 221 is a circular plane or a rectangular plane, its structure is simple. When the second top pressing surface 221 is a rectangular plane, the contact area between the second ejector pin and the welding strip is increased, thereby increasing the area where the welding strip is in close contact with the edge pad 62.

[0069] In a preferred embodiment of the present invention, the first top pressure surface 121 is a rectangular plane, and when the second top pressure surface 221 is a rectangular plane, the width of the second top pressure surface 221 is greater than the width or diameter of the welding strip, and the length of the second top pressure surface 221 is less than the length of the first top pressure surface 121.

[0070] Specifically, when the second top pressing surface 221 is a rectangular plane, the width of the second top pressing surface 221 can be equal to the width of the first top pressing surface 121. The width of the second top pressing surface 221 can be 3mm-10mm. The length of the second top pressing surface 221 can be 2mm-5mm. When the width of the second top pressing surface 221 is greater than the width or diameter of the welding strip, it can ensure that the welding strip is fully in contact with the edge pad 62 on the battery cell 6, thereby ensuring the welding effect.

[0071] Through actual tests or simulation tests, it is found that when the ejector pin module is used to weld the battery cell and the welding strip, the false welding rate can be reduced by more than 5%.

[0072] In a second aspect, the embodiment of the utility model further discloses a welding device, comprising any one of the ejector modules mentioned above. Since the welding device comprises the ejector module mentioned above, it also has the beneficial effects of the ejector module mentioned above, which will not be described in detail here.

[0073] In a preferred embodiment of the present invention, the welding device is used for welding the battery cell 6 to the welding strip, and the battery cell 6 is a back contact battery cell and / or a busbar-less battery cell.

[0074] The light-receiving surface of the back contact cell has no electrode, and the positive and negative electrodes are both set on the backlight side of the cell, which can reduce the blocking of the light-receiving surface of the cell by the electrode, increase the light-receiving area of ​​the light-receiving surface of the cell, and improve the energy conversion efficiency of the cell. Only fine grid lines are set on the busbar-free cell, and the busbar lines are removed, saving the slurry consumed by the busbar lines.

[0075] Reference Figure 6 and Figure 7 The welding equipment also includes a welding table 4 and a heating adsorption device 5.

[0076] The first ejector pin 1 and the second ejector pin 2 can be lifted and lowered on the welding table 4 by a lifting assembly. The lifting assembly may include a cylinder. A plurality of strip grooves 41 are provided on the welding table 4. During the welding process between the battery cell 6 and the welding strip, the lifting assembly drives the first ejector pin 1 and the second ejector pin 2 to rise, so that the first ejector pin 1 and the second ejector pin 2 press the welding strip against the battery cell 6. After the welding between the battery cell 6 and the welding strip is completed, the lifting assembly drives the first ejector pin 1 and the second ejector pin 2 to descend, so that the first ejector pin head 12 and the second ejector pin head 22 fall into the strip groove 41.

[0077] The heating adsorption device 5 includes a plurality of heating elements 51 and a plurality of adsorption pressure pins 52. The heating element 51 may be an infrared lamp tube, or a laser emitter, a hot air emitter, etc. The adsorption pressure pin 52 includes a pressure pin and a suction nozzle connected to the pressure pin. The plurality of adsorption pressure pins 52 are used to press the front of the battery cell 6 during welding. The plurality of adsorption pressure pins 52 are also used to adsorb the battery cell 6 after welding is completed.

[0078] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0079] The embodiments of the utility model are described above in conjunction with the accompanying drawings, but the utility model is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the enlightenment of the utility model, ordinary technicians in this field can also make many forms without departing from the scope of protection of the utility model and the claims, which all fall within the protection of the utility model.

Claims

1. A ejector pin module, characterized in that: The device comprises at least one first ejector pin, wherein the first ejector pin comprises a first ejector pin body and a first ejector pin head connected to the first ejector pin body, wherein the first ejector pin head has a first ejection pressing surface away from the first ejector pin body; When the first ejector pin pushes the solder strip onto the battery cell, the length direction of the first pressing surface is parallel to the extension direction of the solder strip, and the orthographic projection of the first pressing surface on the battery cell covers at least two solder pads.

2. The ejector pin module according to claim 1, characterized in that: The length of the first pressing surface is greater than or equal to 2 mm and less than or equal to 10 mm.

3. The ejector pin module according to claim 1, characterized in that: A first groove is formed on the first pressing surface, and the first groove penetrates the first ejector pin along the length direction of the first ejector pin. The width of the first groove is less than or equal to half of the width or half of the diameter of the welding strip.

4. The ejector pin module according to claim 1, characterized in that: The width of the first pressing surface is greater than the width or diameter of the welding strip.

5. The ejector pin module according to claim 4, characterized in that: The width of the first pressing surface is greater than or equal to 3 mm and less than or equal to 10 mm.

6. The ejector pin module according to claim 1, characterized in that: The first pressing surface of the first ejector needle head is wavy in shape, and the first ejector needle head with a wavy first pressing surface has at least two crests and at least one trough, and the crests and the troughs are alternately arranged along the length direction of the first ejector needle head.

7. The ejector pin module according to claim 1, characterized in that: A plurality of the first ejector pins are arranged in an array to form a first ejector pin assembly, and the ejector pin module further comprises second ejector pins located on both sides of the first ejector pin assembly along a first direction, and the first direction is parallel to a length direction of the first ejector pressing surface; The second ejector pin includes a second ejector pin body and a second ejector pin head connected to the second ejector pin body, the second ejector pin head has a second pressing surface away from the second ejector pin body, and the area of ​​the second pressing surface is less than or equal to the area of ​​the first pressing surface.

8. The ejector pin module according to claim 7, characterized in that: The first ejector pin is T-shaped, and the second ejector pin is inverted L-shaped.

9. The ejector pin module according to claim 7, characterized in that: The second pressing surface is a circular plane or a rectangular plane; When the second ejector pin presses the welding strip, and the second pressing surface is a rectangular plane, the length direction of the second pressing surface is parallel to the extending direction of the welding strip.

10. The ejector pin module according to claim 9, characterized in that: The first pressing surface is a rectangular plane. When the second pressing surface is a rectangular plane, the width of the second pressing surface is greater than the width or diameter of the welding strip, and the length of the second pressing surface is less than or equal to the length of the first pressing surface.

11. The ejector pin module according to claim 7, characterized in that: A plurality of the first ejector pins and two of the second ejector pins spaced apart and distributed along the first direction form an ejector pin group, and the sum of the number of the first ejector pins and the number of the second ejector pins in the ejector pin group is 5 to 10.

12. The ejector pin module according to claim 1, characterized in that: The first ejector main body includes a first needle body connected to the first ejector head, and the number of the first needle bodies is one or two; When the number of the first needle bodies is two, the two first needle bodies are arranged at intervals along the length direction of the first ejector needle head.

13. A welding device, characterized in that: The invention comprises the ejector pin module according to any one of claims 1 to 12.

14. The welding device according to claim 13, characterized in that The welding device is used for welding a battery cell and a welding strip, wherein the battery cell is a back contact battery cell and / or a main grid-free battery cell.

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