CN116079173A

CN116079173A - Welding strip pressing device, series welding machine and welding method of welding strip and battery piece

Info

Publication number: CN116079173A
Application number: CN202211335275.1A
Authority: CN
Inventors: 张舒; 杨泽民; 丁忆; 王乐
Original assignee: Trina Solar Co Ltd
Current assignee: Trina Solar Co Ltd
Priority date: 2022-10-28
Filing date: 2022-10-28
Publication date: 2023-05-09
Also published as: WO2024087723A1

Abstract

The application provides a welding strip pressing device, a series welding machine and a welding method of a welding strip and a battery piece. The compressing device comprises: a pressing plate; the pressing needle groups are arranged on the pressing plate at intervals along the first direction, each pressing needle group is provided with a first pressing needle and a second pressing needle, the first pressing needle and the second pressing needle are spaced by a preset distance along the first direction, and one ends of the first pressing needle and the second pressing needle, which are far away from the pressing plate, are provided with pressing heads; and the plurality of heating through holes penetrate through the pressing plate along the thickness direction of the pressing plate, and the plurality of heating through holes are distributed at intervals along the first direction, wherein a gap between a first pressing needle and a second pressing needle in each pressing needle group corresponds to at least one heating through hole. The compaction device and the series welding machine can selectively heat the welding spot area through the corresponding heating through holes in the gaps between the compaction needle groups, and are favorable for avoiding warping of the battery piece due to higher temperature difference and avoiding failure of the insulating adhesive.

Description

Welding strip pressing device, series welding machine and welding method of welding strip and battery piece

Technical Field

The application mainly relates to the field of photovoltaics, in particular to a welding strip pressing device, a series welding machine and a welding method of a welding strip and a battery piece.

Background

In the production of photovoltaic, a solder strip is required to be soldered to the battery sheet. The welding process is basically as follows, the battery piece realizes the welding procedure through an automatic series welding machine, in the welding process, the welding strip is contacted with the electrode area of the battery piece through a positioning step, the welding strip is tightly attached to the surface of the electrode by utilizing a pressing tool, then the welding strip enters a heating lamp box, and the welding strip and the electrode shape of the battery piece are welded together under the action of an external infrared heat source, a hot air heat source, a laser heat source and the like. In single-sided welding, the battery plate may warp due to heat, and heat radiation may cause the insulation paste on the battery plate to fail.

Therefore, how to avoid the warpage of the battery plate caused by heating during welding and avoid the failure of the insulating adhesive is a problem to be solved.

Disclosure of Invention

The technical problem to be solved in the application is to provide a welding strip compressing device, a series welding machine and a welding method of a welding strip and a battery piece, wherein the compressing device, the series welding machine and the welding method can avoid warping of the battery piece caused by higher temperature difference during welding, and avoid failure of insulating glue.

The application is for solving above-mentioned technical problem and the technical scheme who adopts is a welding strip closing device, includes: a pressing plate; the pressing needle groups are arranged on the pressing plate at intervals along a first direction, each pressing needle group is provided with a first pressing needle and a second pressing needle, the first pressing needles and the second pressing needles are spaced by a preset distance along the first direction, and one ends, far away from the pressing plate, of the first pressing needles and the second pressing needles are provided with pressing heads; and a plurality of heating through holes penetrating through the pressing plate along the thickness direction of the pressing plate, wherein the plurality of heating through holes are distributed at intervals along the first direction, and gaps between the first pressing needles and the second pressing needles in each pressing needle group correspond to at least one heating through hole.

In an embodiment of the present application, a portion of the first pressing needle is movably connected with the pressing plate along an axial direction of the first pressing needle, and a portion of the second pressing needle is movably connected with the pressing plate along an axial direction of the second pressing needle.

In an embodiment of the present application, the pressing plate has a plurality of pressing pin holes, one end of the part of the first pressing pin, which is far away from the pressing head, is disposed in the corresponding pressing pin hole along the axial direction, and one end of the part of the second pressing pin, which is far away from the pressing head, is disposed in the corresponding pressing pin hole.

In an embodiment of the present application, the pressing device further includes a plurality of springs, the springs are sleeved on the part of the first pressing pins, the springs are sleeved on the part of the second pressing pins, one end of each spring is abutted to the pressing plate, and the other end of each spring is abutted to the corresponding pressing heads of the first pressing pins and the second pressing pins.

In an embodiment of the present application, a cross-sectional area of the ram of the first presser pin is larger than a cross-sectional area of the main body portion of the first presser pin, and a cross-sectional area of the ram of the second presser pin is larger than a cross-sectional area of the main body portion of the second presser pin.

In an embodiment of the present application, a plurality of light-transmitting windows are formed on the pressing plate.

The application still provides a series welding machine for solving above-mentioned technical problem, includes: a heating unit; and a compacting device as described above, said compacting device being located below said heating unit.

In an embodiment of the present application, the device further includes a light shielding plate, where the light shielding plate is disposed between the heating unit and the pressing device.

The application also provides a welding method for the welding strip and the battery piece, which is characterized in that the welding strip and the welding spot of the battery piece are welded by using the series welding machine, and when welding, the heating through hole is overlapped with the corresponding welding spot along the projection of the thickness direction, wherein the heating unit heats the welding spot corresponding to the heating through hole through the heating through hole.

In one embodiment of the present application, the method further comprises applying an intermediary to the solder joint prior to soldering.

The compaction device and the series welding machine can selectively heat the welding spot area through the corresponding heating through holes in the gaps between the compaction needle groups, and are favorable for avoiding warping of the battery piece due to higher temperature difference and avoiding failure of the insulating adhesive.

Drawings

In order to make the above objects, features and advantages of the present application more comprehensible, embodiments accompanied with figures are described in detail below, wherein:

FIG. 1 is a schematic front view of a stringer according to an embodiment of the present disclosure;

FIG. 2 is a schematic left-hand view of a stringer according to an embodiment of the present application;

FIG. 3 is a schematic top view of a stringer according to an embodiment of the present application;

FIG. 4 is an enlarged partial view of the rectangular dashed box portion of FIG. 1;

FIG. 5 is an enlarged partial view of the encircled portion of FIG. 4;

FIG. 6 is an enlarged view of a portion of the encircled portion of FIG. 3;

FIG. 7 is a schematic top view of a platen according to one embodiment of the present application.

Detailed Description

In order to make the above objects, features and advantages of the present application more comprehensible, embodiments accompanied with figures are described in detail below.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application, but the present application may be practiced otherwise than as described herein, and therefore the present application is not limited to the specific embodiments disclosed below.

As used in this application and in the claims, the terms "a," "an," "the," and/or "the" are not specific to the singular, but may include the plural, unless the context clearly dictates otherwise. In general, the terms "comprises" and "comprising" merely indicate that the steps and elements are explicitly identified, and they do not constitute an exclusive list, as other steps or elements may be included in a method or apparatus.

In addition, the terms "first", "second", etc. are used to define the components, and are merely for convenience of distinguishing the corresponding components, and unless otherwise stated, the terms have no special meaning, and thus should not be construed as limiting the scope of the present application. Furthermore, although terms used in the present application are selected from publicly known and commonly used terms, some terms mentioned in the specification of the present application may be selected by the applicant at his or her discretion, the detailed meanings of which are described in relevant parts of the description herein. Furthermore, it is required that the present application be understood, not simply by the actual terms used but by the meaning of each term lying within.

Flowcharts are used in this application to describe the operations performed by systems according to embodiments of the present application. It should be understood that the preceding or following operations are not necessarily performed in order precisely. Rather, the various steps may be processed in reverse order or simultaneously. At the same time, other operations are added to or removed from these processes.

Fig. 1 is a schematic front view of a stringer according to an embodiment of the present application, fig. 2 is a schematic left view of the stringer according to an embodiment of the present application, and fig. 3 is a schematic top view of the stringer according to an embodiment of the present application. Referring to fig. 1, the string welder 100 has a case 110, a heating unit 120 positioned inside the case 110, and a conveyor 130. The heating unit 120 includes components such as an infrared heating lamp, a hot air heater, etc. that can be used to heat the belt, the conveyor belt 130 is positioned below the heating unit 120, and the heating unit 120 can heat objects positioned on the conveyor belt 130.

The welding process of the welding strip and the battery piece is as follows. Referring to the top view shown in fig. 3, 3 battery pieces 140 are adjacently distributed along a first direction D1 on the conveyor belt 130, and 8 welding strips 150 are laid on each battery piece. Referring to fig. 1, fig. 1 shows a state in which the transfer belt 130 transfers the attached solder ribbon and battery tab into the case 110. Referring to the left view shown in fig. 2, before the welding strip 150 and the battery cell 140 enter the case 110, an external force toward the battery cell 140 is applied to the welding strip 150 by the pressing device 160, so that the welding strip 150 is attached to the battery cell 140. Then, the conveyor belt 130 carries the solder strip 150 and the battery pieces 140 into the case 110. The welding strip 150 is welded to the welding spot on the battery sheet 140 under the heating of the heating unit 120.

It should be noted that the above description is only exemplary and not limiting to the present application. For example, the arrangement and the number of the battery pieces at the time of welding are not limited to the above examples, and the specific number of the welding strips may be set according to actual requirements, and are not limited to the above 8 strips.

The compressing device can avoid the battery piece from warping due to heating and avoid the failure of insulating glue on the battery piece.

The compression device of the present application will be described with reference to specific examples.

Fig. 4 is a partial enlarged view of a rectangular dotted frame portion in fig. 1. Referring to fig. 4, the pressing device includes a pressing plate 161, a plurality of pressing pin groups 162, and a plurality of heating through holes 163.

Specifically, the platen 161 has opposite first and

second surfaces

161a and 161b in the thickness direction D2. Wherein, as shown in fig. 1, during welding, the first surface 161a faces the heating unit 120 and the second surface 161b faces the battery sheet 140. The pressing plate 161 has a thickness H1 in the thickness direction D2, that is, a distance H1 in the thickness direction D2 between the first surface 161a and the second surface 161b. Referring to fig. 3, the pressing plate 161 has a width W1 in the first direction D1 and a length L1 in the third direction D3. It is understood that the length L1, the width W1 and the thickness H1 of the pressing plate 161 are not limited in this application, and may be set according to actual requirements.

With continued reference to fig. 4, 8 presser finger sets 162 are shown in fig. 4, the 8 presser finger sets 162 being disposed on the presser plate 161 at intervals along the first direction D1.

To facilitate understanding of the arrangement of the pressing needle group in the present application, the description is provided herein with reference to fig. 3 and 4. As shown in fig. 3, the pressing pin groups 162 spaced apart in the first direction D1 and the third direction D3 are distributed on the pressing plate 161 located at the far right in fig. 3. Wherein, 8 presser finger groups 162 are arranged at intervals in the first direction D1, and 8 presser finger groups 162 are also arranged at intervals in the third direction D3. In fig. 4, only 8 presser groups 162 arranged at intervals in the first direction D1 are shown in fig. 4 for view angle reasons. As shown in fig. 4, the distance between two pressing pin groups 162 adjacent in the first direction D1 is related to the distance between two welding spots 141 adjacent in the first direction D1 on the battery sheet 140, which will be described later. The distance between two adjacent press pin sets 162 along the third direction D3 is related to the distance between two adjacent bonding tapes 150 along the third direction D3, and when the distance between two adjacent bonding tapes along the third direction D3 increases, the distance between two adjacent press pin sets along the third direction D3 also increases so as to ensure that the press pin sets can be accurately pressed on the bonding tapes. It will be appreciated that the number of the pressing needle groups in the pressing device in the present application is not limited to the number in the above embodiment, and may be set according to actual requirements.

The following describes the presser group in detail by way of examples.

Fig. 5 is a partially enlarged view of the circled portion in fig. 4, and fig. 6 is a partially enlarged view of the circled portion in fig. 3. Referring to fig. 5, the presser group has a first presser 162a and a second presser 162b, with the axis of the first presser 162a and the axis of the second presser 162b being spaced apart by a preset distance L2 along a first direction D1. One end of the first pressing needle 162a and one end of the second pressing needle 162b are connected with the pressing plate 161, and one end of the first pressing needle 162a and one end of the second pressing needle 162b, which are far away from the pressing plate 161, are respectively provided with a first pressing head 162a-1 and a second pressing head 162b-1.

In some embodiments, referring to fig. 5, the pressing plate 161 has a plurality of pressing holes (not shown), and one end of a part of the first pressing needle 162a of the pressing device, which is far away from the first pressing head 162a-1, is disposed in the corresponding pressing hole along the axial direction, and one end of a part of the second pressing needle 162b of the pressing device, which is far away from the second pressing head 162b-1, is disposed in the corresponding pressing hole. The part of the first pressing needle and the part of the second pressing needle can move along the respective axial directions in the pressing needle hole where the part of the first pressing needle and the part of the second pressing needle are located, namely are movably connected with the pressing plate 161 along the thickness direction D2.

With continued reference to FIG. 5, the compression device further includes a plurality of springs 164. Specifically, referring to fig. 5, a spring 164 is sleeved on each of a first pressing pin 162a and a second pressing pin 162b movably connected to the pressing plate 161. One end of the spring 164 is abutted against the pressing plate 161, and the other end is abutted against the first pressing head 162a-1 of the corresponding first pressing pin 162a and the second pressing head 162b-1 of the corresponding second pressing pin 162 b. When the first pressing head 162a-1 applies pressure to the welding strip 150 to be attached to the battery piece 140, the spring 164 sleeved on the first pressing needle 162a can prevent the battery piece 140 from being broken due to impact of rigid pressure. The above description is also applicable to the second pressing needle 162b, and will not be described in detail.

It should be noted that the first pressing needle and the second pressing needle in the same pressing needle group may be both movably connected to the pressing plate along the thickness direction D2, or any one may be movably connected to the pressing plate, and the other may be fixedly connected to the pressing plate. The application does not limit the quantity of first pressure needle and second pressure needle of thickness direction D2 swing joint with the clamp plate, when partial first pressure needle and partial second pressure needle and clamp plate swing joint, the first pressure needle and the second pressure needle of surplus portion can with clamp plate fixed connection, when swing joint's first pressure needle and second pressure needle apply pressure to the welding strip and make it paste mutually with the battery piece, the spring of cover on this partial first pressure needle and second pressure needle can provide the buffering for first pressure needle and the second pressure needle with clamp plate fixed connection, avoid leading to the battery piece to break.

Referring to FIG. 5, in other embodiments, the cross-sectional area of the first ram 162a-1 of the first striker 162a is greater than the cross-sectional area of the first body portion 162a-2 of the first striker 162 a. Similarly, the cross-sectional area of the second ram 162b-2 of the second pin 162b is greater than the cross-sectional area of the second body portion 162b-2 of the second pin 162 b. The cross-sectional area of the first ram 162a-1 refers to: the above description is equally applicable to the first body portion 162a-2, the second ram 162b-1, and the second body portion 162b-2 in terms of the area of the cross section of the first ram 162a-1 perpendicular to the thickness direction D2, and will not be repeated here. The first pressure head and the second pressure head are used for applying pressure to the welding strip 150, and the area of the first pressure head and the area of the second pressure head are increased, so that the welding strip and the battery piece can be prevented from being broken due to the fact that the welding strip and the battery piece are subjected to larger pressure.

Returning to fig. 4, the pressing device further includes a plurality of heating through holes 163, the plurality of heating through holes 163 being arranged at intervals in the first direction D1, the heating through holes 163 penetrating the pressing plate 161 in the thickness direction D2. The gap between the first and

second pins

162a and 162b in each pin group 162 corresponds to at least one heating through hole 163. Specifically, referring to fig. 5, it can be seen that there is a gap 162c between the first presser 162a and the second presser 162b, the gap 162c corresponding to one heating through hole 163 in the thickness direction D2. Referring to fig. 5, the size of the gap 162c in the thickness direction D2 may be changed by adjusting the preset distance L2.

At the time of welding, the first and

second pins

162a and 162b are distributed on both sides of the welding spot 141 in the first direction D1, the heating through hole 163 is located above the welding spot 141 in the thickness direction D2, and projections of the heating through hole 163 and the welding spot 141 in the thickness direction D2 overlap. As shown in fig. 1, when the heating unit 120 heats the solder ribbon 150 and the battery sheet 140, the heat radiation released from the heating unit 120 may heat the solder joint 141 corresponding to the heating through-hole 163 located on the pressing plate 161 through the heating through-hole 163. For the non-welding spot area on the battery piece, the pressing plate 161 positioned between the non-welding spot area and the heating unit can prevent the heat radiation released by the heating unit from directly irradiating the battery piece in the non-welding spot area, so, compared with the technical scheme of the battery piece in the non-welding spot area directly irradiated by the heat radiation in the conventional technology, the welding strip pressing device can effectively reduce the peak temperature of the battery piece, thereby reducing the temperature difference of the battery piece before and after welding, further avoiding the warping of the battery piece caused by larger temperature difference, and avoiding the heat radiation released by the heating unit from directly irradiating the photoresist, thereby avoiding the failure of the insulating adhesive between the welding strip and the battery piece caused by high temperature.

Fig. 6 is an enlarged view of a part of the circled portion in fig. 3, and further description will be made with reference to fig. 5 and 6 for more clearly understanding the positional relationship among the pin group, the heating through hole, and the solder joint at the time of soldering.

In fig. 6, the first and

second pins

162a and 162b are distributed on both sides of the welding spot 141 in the first direction D1. In fig. 6, the cross sections of the first presser finger 162a and the second presser finger 162b are circular, and are tangent to both side edges of the welding spot 141, respectively. Referring to fig. 5, in order to improve the efficiency of welding the solder ribbon 150 and the solder joint 141 by heat radiation through the heating through hole 163, the first and/or

second pins

162a and 162b should be prevented from overlapping with the projection of the solder joint 141 in the thickness direction D2 as much as possible. It will be appreciated that the first and/or

second pins

162a, 162b are allowed to partially overlap the projected portion of the solder joint 141 in the thickness direction D2, but the first and

second pins

162a, 162b should not completely cover the solder joint 141.

With continued reference to fig. 5, in some embodiments, the cross-section of the heating via 163 perpendicular to the thickness direction D2 may be coincident with the solder joint 141 or may be different. The projections of the heating through-hole 163 and the solder joint 141 in the thickness direction D2 are partially overlapped, so that the heat radiation released from the heating unit can effectively solder the solder ribbon and the solder joint. In other embodiments, the number of the heating through holes 163 corresponding to the gaps 162c of the presser finger set 162 in the thickness direction D2 is not limited to one in fig. 5, and may be any number such as two or three, for example.

Referring to fig. 7, a top view of a platen according to an embodiment of the present application is shown. In some embodiments, the platen 161 is provided with a plurality of light-transmitting windows 161c. Specifically, as shown in fig. 7, the light-transmitting windows 161c extend along the first direction D1, and the plurality of light-transmitting windows 161c are spaced apart along the third direction D3. The light-transmitting window 161c allows the heat radiation to heat a specific region on the battery sheet, improving heating efficiency. It will be appreciated that the number, shape and area of the light-transmitting windows may be set as desired and are not limited to the embodiment shown in fig. 7.

According to the pressing device, the welding spot area can be selectively heated through the heating through holes corresponding to the gaps between the pressing needle groups, so that the temperature difference of the battery piece before and after welding is reduced, the battery piece is prevented from being warped due to the larger temperature difference, and insulating glue between the welding strip and the battery piece is prevented from being invalid due to high temperature.

The application also provides a series welding machine for solving the problems. Referring to fig. 1, a string welder 100 includes: a heating unit 120 and a compacting apparatus 160 as described hereinbefore. The pressing device 160 applies an external force to the welding strip 150 to make it fit with the welding spot on the battery piece 140, and the welding strip 150 and the battery piece 140 are welded together under the action of the heating unit 120.

In one embodiment, the stringer 100 also includes a shield 170. Referring to fig. 1, a light shielding plate 170 is disposed between the heating unit 120 and the pressing device 160. In fig. 1, the light shielding plate 170 corresponds to a gap between two adjacent battery pieces 140 in the thickness direction D2, so that the insulation paste coated on the solder tape between the battery pieces can be prevented from being failed due to high temperature. For further details on the stringer, reference may be made to the foregoing related description, which is not repeated here.

The series welding machine in the embodiment of the application can selectively heat the welding spot area by arranging the heating through holes corresponding to the gaps between the pressing pin groups, is beneficial to avoiding warping caused by heating of the battery piece, and avoids failure of the insulating adhesive.

The application also provides a welding method for the welding strip and the battery piece for solving the problems. Referring to fig. 2, the welding method welds the welding strip 150 to the welding spot of the battery cell 140 using the series welding machine as described above, and there is an overlap of the heating through-holes 163 with the projections of the corresponding welding spots in the thickness direction D2 at the time of welding. Wherein the heating unit 120 heats the welding spot corresponding to the heating through hole 163 through the heating through hole 163.

Referring to fig. 5, in one embodiment, an interposer 180 is applied to the solder joints 141 prior to soldering. Interposer 180 includes one or more of conductive solder paste, conductive tape, or conductive glue. The interposer aids in soldering the solder strip to the solder joint 141.

According to the welding method in the embodiment, when the welding is performed, the heating through holes are overlapped with the corresponding welding spots along the projection of the thickness direction, so that the battery piece is prevented from being warped due to the large temperature difference, and the insulating adhesive between the welding strip and the battery piece is prevented from being invalid due to the high temperature.

While the basic concepts have been described above, it will be apparent to those skilled in the art that the foregoing application disclosure is by way of example only and is not intended to be limiting. Although not explicitly described herein, various modifications, improvements, and adaptations of the present application may occur to one skilled in the art. Such modifications, improvements, and modifications are intended to be suggested within this application, and are therefore within the spirit and scope of the exemplary embodiments of this application.

Meanwhile, the present application uses specific words to describe embodiments of the present application. Reference to "one embodiment," "an embodiment," and/or "some embodiments" means that a particular feature, structure, or characteristic is associated with at least one embodiment of the present application. Thus, it should be emphasized and should be appreciated that two or more references to "an embodiment" or "one embodiment" or "an alternative embodiment" in various positions in this specification are not necessarily referring to the same embodiment. Furthermore, certain features, structures, or characteristics of one or more embodiments of the present application may be combined as suitable.

In some embodiments, numbers describing the components, number of attributes are used, it being understood that such numbers being used in the description of embodiments are modified in some examples by the modifier "about," approximately, "or" substantially. Unless otherwise indicated, "about," "approximately," or "substantially" indicate that the number allows for a 20% variation. Accordingly, in some embodiments, numerical parameters set forth in the specification and claims are approximations that may vary depending upon the desired properties sought to be obtained by the individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and employ a method for preserving the general number of digits. Although the numerical ranges and parameters set forth herein are approximations that may be employed in some embodiments to confirm the breadth of the range, in particular embodiments, the setting of such numerical values is as precise as possible.

Claims

1. A welding strip hold down device, comprising:

a pressing plate;

the pressing needle groups are arranged on the pressing plate at intervals along a first direction, each pressing needle group is provided with a first pressing needle and a second pressing needle, the first pressing needles and the second pressing needles are spaced by a preset distance along the first direction, and one ends, far away from the pressing plate, of the first pressing needles and the second pressing needles are provided with pressing heads; and

the plurality of heating through holes penetrate through the pressing plate in the thickness direction of the pressing plate, and are distributed at intervals in the first direction, wherein gaps between the first pressing needles and the second pressing needles in each pressing needle group correspond to at least one heating through hole.

2. The compression device of claim 1, wherein a portion of the first compression pin is movably coupled to the compression plate along an axial direction of the first compression pin and a portion of the second compression pin is movably coupled to the compression plate along an axial direction of the second compression pin.

3. The compression device of claim 2, wherein the compression plate has a plurality of compression pin holes, wherein an end of the portion of the first compression pin remote from the compression head thereof is disposed in the corresponding compression pin hole along the axial direction thereof, and wherein an end of the portion of the second compression pin remote from the compression head thereof is disposed in the corresponding compression pin hole.

4. The compression device of claim 3, further comprising a plurality of springs, wherein the springs are sleeved on the portion of the first compression pin, the springs are sleeved on the portion of the second compression pin, wherein one end of each spring is abutted against the pressing plate, and the other end is abutted against the pressing heads of the corresponding first compression pin and second compression pin.

5. The compression device of claim 1, wherein the cross-sectional area of the ram of the first compression pin is greater than the cross-sectional area of the body portion of the first compression pin and the cross-sectional area of the ram of the second compression pin is greater than the cross-sectional area of the body portion of the second compression pin.

6. The compression device of claim 1, wherein the compression plate is provided with a plurality of light-transmitting windows.

7. A stringer, comprising:

a heating unit; and

a compacting apparatus according to any one of claims 1 to 6, which is located below the heating unit.

8. The stringer of claim 7, further comprising a mask disposed between the heating unit and the compression device.

9. A method for welding a welding strip and a battery piece, characterized in that the welding strip is welded to a welding spot of the battery piece by using the series welding machine as claimed in claim 7 or 8, and when welding, the heating through hole overlaps with a projection of a corresponding welding spot in the thickness direction, wherein the heating unit heats the welding spot corresponding to the heating through hole through the heating through hole.

10. The method of welding according to claim 9, further comprising applying an intermediary to said weld spot prior to welding.