CN220312097U

CN220312097U - Series welding system for battery pieces

Info

Publication number: CN220312097U
Application number: CN202321918125.3U
Authority: CN
Inventors: 卓壮; 高德照; 许成涛; 康凌; 滕晓晓
Original assignee: Suzhou Wisdom Valley Laser Intelligent Equipment Co Ltd
Current assignee: Suzhou Wisdom Valley Laser Intelligent Equipment Co Ltd
Priority date: 2023-07-20
Filing date: 2023-07-20
Publication date: 2024-01-09
Anticipated expiration: 2033-07-20

Abstract

The utility model belongs to the technical field of battery piece welding, and provides a battery piece series welding system which is used for solving the problems of low welding efficiency, short service life and the like of a battery piece in the prior welding technology. The battery piece series welding system comprises a transfer device and a battery piece series welding device; the transferring device is used for transferring the battery piece loaded with the welding band group to a welding station and/or transferring the battery piece serial welding device to the welding station; the battery piece series welding device is used for uniformly radiating VCSEL laser to the battery piece so as to realize the welding of the grid electrode bonding pad and the bonding tape on the surface of the battery piece. The battery piece series welding system provided by the utility model can reduce the response time and the welding time in the welding process, improves the light energy absorption efficiency of the battery piece, is easier to control the overtemperature risk, can effectively prolong the service life of the battery piece series welding system, ensures that the battery piece automatically flows to the welding station through the transfer device, and ensures the orderly execution of series welding work.

Description

Series welding system for battery pieces

Technical Field

The utility model relates to the technical field of battery piece welding, in particular to a battery piece series welding system.

Background

In the preparation process of the photovoltaic module, the battery pieces are required to be connected through welding strips to form a battery string, and in order to weld the welding strips on the battery pieces, the technology adopted at present comprises various automatic welding methods such as hot air welding, electromagnetic induction welding, infrared welding and the like. The infrared welding process is developed most mature, has the advantages of low equipment cost, direct heating of objects and the like, and obtains good welding effect, but the mode has certain defects, firstly, the welding response is delayed, and the process of gradually heating the welded materials for welding generally needs 1-3s. And secondly, the electro-optical conversion efficiency is low, and the light energy is easily absorbed by other materials in the optical guiding process, so that the light energy utilization rate is further reduced. And secondly, the power of infrared light is difficult to control stably, so that the overtemperature risk of the material is easy to raise, and accurate temperature control is not easy to realize. Secondly, the service life of the infrared heating lamp tube is usually only about 3000-5000 hours, and the equipment maintenance cost is high. Finally, for welding the battery piece, as the material of the battery piece is mainly a silicon wafer, the wavelength in the high-efficiency range of the absorption spectrum of the silicon material and infrared light are also greatly different, so that the effective absorption and utilization rate of the silicon wafer to light energy is relatively low.

Disclosure of Invention

In order to solve the technical problems, the battery piece series welding system provided by the utility model can effectively reduce the response time of the welding process, improve the light energy absorption efficiency of the battery piece, reduce the overtemperature risk and prolong the service life of welding consumables.

The utility model provides a battery piece series welding system which comprises a transfer device and a battery piece series welding device;

the transferring device is used for transferring the battery piece loaded with the welding band group to a welding station and/or transferring the battery piece serial welding device to the welding station;

the battery piece series welding device is used for uniformly radiating VCSEL laser to the battery piece so as to realize the welding of the main grid bonding pad and the welding strip on the surface of the battery piece.

Specifically, the battery piece series welding device comprises a heating module, wherein the heating module comprises a heat sink and a plurality of VCSEL laser chips, the VCSEL laser chips are orderly arranged on the heat sink in an array mode, positive and negative connecting terminals are arranged on the heat sink and are used for being connected with a power supply to electrify the VCSEL laser chips.

Specifically, the battery piece series welding device further comprises an installation box, and the heating module is installed on the installation box or a plurality of heating modules are mutually spliced on the installation box, so that a plurality of VCSEL laser chips form a luminous radiation surface with the irradiation area of the battery piece.

Specifically, the light transmission opening is formed in the mounting box, the heating modules are mounted in the mounting box, laser of the VCSEL laser chip irradiates the battery piece through the light transmission opening, and protective glass is mounted at the position of the light transmission opening and used for protecting the VCSEL laser chip.

Specifically, the two sides of the protective glass are plated with an antireflection film, and the antireflection film is used for selectively filtering laser with the wavelength of 920 nm-960 nm.

Specifically, install the heat-conducting plate on the mounting box, the heat-conducting plate laminating is in a plurality of the heat sink deviates from the one side of VCSEL laser chip, still be equipped with in the mounting box and be used for right the heat-conducting plate carries out refrigerated cooling mechanism.

Specifically, the inside of heat-conducting plate is equipped with the cooling water route, cooling mechanism includes the fixed mounting cooling water route import and export water pipe head of position department.

Specifically, a first sensor is arranged on the heat conducting plate and used for detecting the working temperature of the heat conducting plate.

Specifically, the cooling water path extends along the length direction of the heating module and fully covers all the heating modules in the width direction of the cooling water path, and the first sensors are uniformly distributed on the heat conducting plate corresponding to the positions of each cooling water path in the length direction of the cooling water path.

Specifically, be equipped with on the mounting box and be used for detecting the second sensor of the temperature of battery piece, the second sensor is non-contact infrared temperature measurement sensor.

Specifically, the output working wavelength of the VCSEL laser chip used on the heat sink is one or a combination of more than one of 808nm, 850nm, 905nm, 940nm and 980 nm.

The beneficial effects are that:

1. the heating module of the battery piece series welding system adopted by the utility model is provided with VCSEL laser chips which are arranged in an ordered array, so that the VCSEL laser chips with single power of only several watts are combined together to form a heating array surface of hundreds of watts to meet the use requirement of welding, the response time of the heating array surface reaches nanosecond level, compared with the traditional infrared light irradiation mode by using an infrared lamp tube, the battery piece can reach the required temperature quickly, and in addition, the emitted laser can directly irradiate the surface of the battery piece, the waste of light source energy caused by the absorption of a corresponding optical light guide system is avoided, and the whole welding time can be greatly shortened; and moreover, the battery piece or the battery piece series welding device can be automatically transferred by adopting the transfer device, so that series welding work can be normally and orderly executed at a welding station, and the process continuity is excellent.

2. According to the battery piece series welding system provided by the utility model, the spectrum of the emitted laser of the VCSEL laser chip is covered between 650nm and 1550nm, the light absorption wavelength of the silicon solar panel made of the silicon material is mainly concentrated in the visible light and near infrared light region, namely, the wavelength is between 400nm and 1100nm, and the silicon material has higher absorptivity to the light in the wavelength range, so that when the working range of the VCSEL laser is between 650nm and 1100nm, the silicon wafer has better absorption performance, and compared with the light source generated by the traditional infrared lamp tube, the silicon solar panel made of the silicon material has better light energy absorption efficiency;

3. according to the battery piece series welding system provided by the utility model, the VCSEL laser chip is used for replacing the traditional infrared laser welding, the actual service life can reach hundreds of thousands of hours, and compared with the service life of the traditional infrared lamp tube which is 5000 hours, the maintenance cost of equipment can be effectively reduced;

4. according to the battery piece series welding system provided by the utility model, the laser array surface of the VCSEL laser chip is directly irradiated on the battery piece, and the electro-optical transmission efficiency is stable, so that accurate and reliable basis can be provided for controlling the temperature rise of the battery piece, the temperature of the battery piece before and after welding can be controlled by changing the power or the length of the working time, and compared with the mode of infrared lamp tube heat radiation, the battery piece series welding system is more controllable, and the overtemperature risk caused by overhigh temperature rise of the battery piece can be effectively reduced;

5. according to the battery piece series welding system, the heating module is cooled through the combined cooling waterway, so that the potential risk of damage caused by overhigh temperature of equipment during working can be prevented; meanwhile, the VCSEL laser chip of the heating module is protected by the protective glass, dust can be effectively prevented from entering to cause abnormal operation of equipment, and in addition, the light source of a wave band for filtering fixed wavelengths is plated with an antireflection film on the protective glass, so that the laser penetrating effect can be improved, and the wavelength range of acting laser can be ensured.

Drawings

Fig. 1 is a schematic structural diagram of a battery piece series welding device provided by the utility model;

FIG. 2 is a schematic view of an assembled structure of a plurality of heating modules provided in the present utility model in a mounting box;

FIG. 3 is a schematic view of a heating module according to the present utility model;

FIG. 4 is a schematic diagram showing the relationship between the absorption coefficient of the optical parameters of the VCSEL chip and the laser band of the VCSEL chip provided by the utility model;

fig. 5 is a schematic structural view of the protective glass provided by the utility model on the mounting box;

FIG. 6 is a schematic view of the structure of the inside of the mounting box provided by the present utility model;

fig. 7 is a front view of the battery piece series welding device provided by the utility model;

fig. 8 is a cross-sectional view of the A-A plane of fig. 7.

In the figure:

100-series welding device of battery pieces;

10-a heating module; 1-a heat sink; 2-VCSEL laser chips; 3-mounting boxes; 4-a heat-conducting plate; 41-a cooling water path; 5-protecting glass; 6-a water inlet joint; 7-water outlet joint.

Detailed Description

Example embodiments will now be described more fully with reference to the accompanying drawings. However, the exemplary embodiments can be embodied in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the example embodiments to those skilled in the art. In the drawings, the thickness of regions and layers are exaggerated for clarity. The same reference numerals in the drawings denote the same or similar structures, and thus detailed descriptions thereof will be omitted.

The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of embodiments of the utility model. One skilled in the relevant art will recognize, however, that the inventive aspects may be practiced without one or more of the specific details, or with other methods, components, materials, etc. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the utility model.

The embodiment described in the following examples is a series welding system for battery cells, and this example is only a part of embodiments of the present utility model, but the protection scope of the present utility model is not limited thereto. All other embodiments, which can be made by those skilled in the art without the inventive effort, are intended to be encompassed within the scope of the present utility model.

The battery piece series welding system provided by the embodiment of the utility model can reduce the response time of the welding process, improve the light energy absorption efficiency of the battery piece, control the overtemperature risk more easily and effectively prolong the service life of the battery piece series welding system; as shown in fig. 1, in order to realize the function of the battery piece serial welding system, the battery piece serial welding system comprises a transfer device and a battery piece serial welding device 100; the transferring device is used for transferring the battery piece loaded with the welding band group to a welding station and/or transferring the battery piece serial welding device 100 to the welding station; the cell string welding device 100 is used for radiating VCSEL laser to the cell to achieve welding of the cell surface grid and the solder strip. The transfer device can automatically and accurately convey the battery piece or the battery piece series welding device 100 so as to adapt to automatic processing of welding the battery piece by equipment. The transfer device in this embodiment includes, but is not limited to, a conveyor belt, a conveyor chain, a linear movement module, etc. which are commonly used in the prior art.

In order to ensure the welding use effect of the battery piece series welding device 100, as shown in fig. 1 to 3, the battery piece series welding device 100 is provided, and comprises a heating module 10, wherein the heating module 10 comprises a heat sink 1 and a plurality of VCSEL laser chips 2, the VCSEL laser chips 2 (COS/COB package) are two-dimensional array area light sources formed by welding hundreds of milliwatt level vertical plane cavity emitting lasers (VCSELs) on a heat sink 1 made of aluminum nitride ceramics or other materials, each VCSEL laser chip 2 can realize power output of up to several watts, is a basic chip unit for manufacturing a rectangular laser module, is not excessively described here, the heat sink 1 can be a gold-plated red copper heat sink, can be used for radiating heat and realizing electric connection by welding the VCSEL laser chips 2, and the VCSEL laser chips 2 are welded above the heat sink 1 in a welding mode, and the VCSEL laser chips 2 are arranged on the heat sink 1 in an ordered array according to fig. 3; in order to ensure the stability of the heating effect, the VCSEL laser chips 2 may be preferably arranged in a honeycomb array to ensure equal spacing between every two adjacent VCSEL laser chips 2; the VCSEL laser chips 2 may be arranged in a matrix manner as shown in fig. 2 and 3, so as to ensure the temperature balance of each irradiation surface, and since the power of a single light emitting point of the VCSEL laser chip 2 is only 1mw-10mw, and only a few watts of output can be formed after the chip is formed by six hundred light emitting points, the actual use requirement of welding cannot be met far, and when the VCSEL laser chip is applied to the welding of a battery piece, the array arrangement of the VCSEL laser chips is combined to form a heating module 10 with hundreds to kilowatts and power, so that the welding use requirement is met (the number of VCSEL laser chips 2 arranged on each heat sink 1 is preferably 700-800).

Further, in order to ensure the normal operation of the heating module 10, positive and negative terminals are provided on the heat sink 1, and the positive and negative terminals are used for switching on a power supply to supply power to all VCSEL laser chips 2. The heating module 10 employing the above-mentioned battery plate can stably provide up to 100W/cm as compared with the conventional infrared lamp tube welding battery plate ² The radiation brightness and the heating rate can reach hundreds of Kelvin per second, so that accurate local laser heat treatment can be provided for a heated object, in addition, as the response time of the VCSEL laser chip 2 is short, the electro-optic response rate is as high as GHz, and the electro-optic conversion efficiency can be stabilized at about 40%, the battery piece can be rapidly heated so as to weld a welding strip on the battery piece, and compared with the traditional infrared lamp tube welding, the welding rate and the efficiency can be effectively improved; the conventional service life of the heating device applied to the VCSEL laser chip 2 can reach 10 ten thousand hours, and compared with 5000 hours of the service life of a common infrared lamp tube, the maintenance cost of equipment can be effectively reduced; compared with the traditional infrared lamp tube, the power of the heating module 10 is more stable, so that the heating temperature of the battery piece is more favorably controlled by controlling the time and the power, and the battery piece is not easy to crack and warp due to overtemperature or damage due to other factors due to strong controllability; as shown in fig. 4, the VCSEL laser-based radiation source has a narrow linewidth radiation spectrum (1 nm-10 nm) that adapts to the absorption of photovoltaic materials, a high-speed response time below nanoseconds, and precisely controllable directivity. The light source is very suitable for high-efficiency heating directional radiation light source for series welding of photovoltaic cells, and the heating module is preferredThe working wave band of 10 is one of 808nm, 850nm, 905nm, 940nm and 980nm, so that laser is easier to be absorbed by a battery piece, and compared with the traditional infrared light source, the waste of the light source can be effectively reduced; in addition, the proper welding power can be adjusted by adjusting the arrangement number of the VCSEL laser chips 2, so that the excellent use effect and the excellent adjustment ductility are achieved. When the battery piece series welding device 100 works, laser with an array surface is emitted to the battery pieces through the plurality of VCSEL laser chips 2, so that the battery pieces absorb light energy, and after the battery pieces are heated, the welding band groups covered on the surfaces of the battery pieces can be melted at the same time, so that welding is realized. The battery piece series welding device 100 can be applied to various welding processes, and has good use benefits.

As a preferred alternative size and parameters: to match the specifications of 210mm×105mm of the battery pieces, a lighting area of the single battery piece heating module 10 is 31.62mm× 244.3mm; the two ends are positive and negative electrode bonding pads, four corners are provided with screw mounting holes, and the middle is also provided with a screw mounting hole; alN (aluminum nitride ceramic) heat sink 1 (here, frame mounting VCSEL laser chip 2) geometry: 3.5mm by 3.5mm; the size of the infrared laser luminous unit is about 1mm multiplied by 1mm, and each unit contains more than 600 VCSEL luminous points; the heating has 6 rows of lasers connected in parallel, 44 VCSEL laser chips 2 in each row are connected in series, the wavelength is 940nm, and the laser output power is 300W-1000W. As shown in FIG. 2, the number of the heating modules 10 is preferably eight, each heating module 10 is independently driven in an electric control manner, the total power is 2.4KW-8.0KW, and the total geometric dimension is 258.5mm multiplied by 270mm.

As shown in fig. 1 and fig. 2, the battery piece series welding device 100 further includes a mounting box 3, where the heating module 10 is mounted on the mounting box 3 or a plurality of heating modules 10 are mounted on the mounting box 3 in a mutually spliced manner, so that a plurality of VCSEL laser chips 2 form a heating surface with a battery piece irradiation area, and in some special heat treatment processes, the heat sink 1 may be designed to match the shape of the material to be heated so as to meet different use requirements. As another preferred embodiment, the plurality of heating modules 10 in the mounting box 3 may be divided into a preheating area and a welding area, wherein one part of the heating modules 10 corresponds to preheating power, the other part of the heating modules 10 corresponds to welding power, the two parts of the heating modules 10 independently operate, the heating modules 10 in the welding area do not operate or stand by during preheating, the heating modules 10 in the preheating area do not operate or stand by during welding, and the battery piece is preheated before welding, so that damage caused by rapid temperature rise of the battery piece can be prevented.

In order to prevent dust from affecting the normal operation of the VCSEL laser chip 2, as shown in fig. 5, a light transmission opening is formed in the mounting box 3, a plurality of heating modules 10 are all mounted in the mounting box 3, and laser beams of the VCSEL laser chip 2 are irradiated on the battery chip through the light transmission opening, at this time, a protective glass 5 is mounted at the position of the light transmission opening, the protective glass 5 is used for protecting the VCSEL laser chip 2, and during mounting, the protective glass 5 should be tightly attached to the working surface of the VCSEL laser chip 2, so as to prevent the influence of smoke dust on the laser chip and ensure the strength of the mounting surface to prevent damage.

In order to prevent hundreds of VCSEL laser chips 2 from working at the same time and having higher temperature and burning out equipment, a heat conducting plate 4 is arranged on a mounting box 3, and the heat conducting plate 4 is attached to one side of a plurality of heat sinks 1, which is away from the VCSEL laser chips 2, so as to be used for absorbing heat of the heat sinks 1, as shown in figures 6 to 8; in order to enhance heat dissipation, a cooling mechanism for cooling the heat conductive plate 4 is also provided in the mounting case 3. As a preferable mode of the above-described technical means, the heat conductive plate 4 may be a copper plate or an aluminum water-cooled heat sink, and the cooling water path 41 may be provided inside the heat conductive plate, and water pipe joints may be provided at the inlet/outlet positions of the cooling water path 41 to dissipate heat generated by water circulation. The water pipe connector comprises a water inlet connector 6 for water inlet and a water outlet connector 7 for water outlet; to enhance the heat conduction efficiency, a metal or nonmetal heat conduction material such as indium foil, silver paste or heat conduction silicone grease may be uniformly filled between the heat conduction plate 4 and the heat sink 1, or a metal solder such as soldering silver paste may be used to solder the heat sink 1 to the heat conduction plate 4.

According to the battery piece series welding system provided by the embodiment of the utility model, the first sensor is arranged on the heat conducting plate 4 and is used for being electrically connected with the control unit to detect the working temperature of each area of the battery piece heating module 10, and when the temperature is too high, emergency alarm or cooling acceleration is needed to be carried out so as to prevent damage to components caused by the fact that the temperature is continuously too high. The control unit is a common control structure in the prior art, and detailed description of a specific control principle of the control unit is omitted here.

In the battery piece series welding system provided by the embodiment of the utility model, as shown in fig. 8, the cooling water paths 41 extend along the length direction of the heating module 10 (the heat sink 1) and realize full coverage of all the heating modules 10 in the width direction, the positions of the heat conducting plates 4 corresponding to each cooling water path 41 are uniformly distributed and provided with the first sensors in the length direction of the cooling water paths 41, preferably, one first sensor is respectively arranged at the front, middle and rear sides of each cooling water path 41 (or one first sensor is uniformly arranged at the front, middle and rear sides of each length direction when the cooling water paths 41 are of an S shape) so as to detect the working temperature of each region, and each first sensor is electrically connected with the control unit. In this embodiment, the first sensor may specifically be a thermistor.

According to the battery piece series welding system provided by the embodiment of the utility model, the anti-reflection films are plated on the two sides of the protective glass 5, the anti-reflection films are used for selectively filtering laser with the wavelength of 920-960 nm, the refractive efficiency of light is improved through the anti-reflection films, the wave bands which do not accord with the preset range are filtered, the efficiency of a workpiece can be improved, and meanwhile, the welding temperature of the surface of the battery piece can be further accurately estimated, so that the system can estimate the actual rising temperature of the battery piece according to the absorption efficiency of the 940nm wavelength to adjust input parameters.

The battery piece series welding system provided by the embodiment of the utility model comprises a feeding mechanism, a discharging mechanism, a battery piece temperature detection system and any battery piece series welding device 100, wherein:

the feeding mechanism is used for supplying the battery piece with the surface covered with the welding strip group to the heating station; the battery piece series welding device 100 is used for irradiating the battery piece to heat the battery piece to melt a welding strip group covered on the surface of the battery piece, the battery piece temperature detection system is used for monitoring the temperature of the surface of the battery piece and feeding back to the closed loop control unit to output a modulation and driving signal applied to the battery piece series welding device 100, and welding is completed after cooling down and cooling, wherein the cooling mode can be natural cooling or programmed cooling, and the system is designed to further comprise a cooling device during programmed cooling, and the cooling device comprises but is not limited to modes of air cooling, water cooling, low-temperature gas (such as nitrogen) refrigeration and the like; in addition, the device can also comprise a heating device for preheating, wherein the heating device is used for preheating the battery piece before welding so as to prevent the battery piece from bending and hidden cracking caused by too fast temperature rise; the discharging mechanism is used for transferring the welded battery string group from the heating station to the next station. The battery piece temperature detection system is used for monitoring the surface temperature in the heating process of the heating device, and performing closed-loop regulation and control on relevant factors such as power, current or heating action time of the series welding system when the temperature is too high.

Wherein the above-mentioned battery temperature detection system may be a second sensor mounted on the mounting box 3, and the second sensor may be an infrared temperature detection sensor for detecting the temperature of the battery.

The above is only a preferred embodiment of the present utility model, and is not intended to limit the present utility model, but various modifications and variations can be made to the present utility model by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present utility model should be included in the protection scope of the present utility model.

Claims

1. The battery piece series welding system is characterized by comprising a transfer device and a battery piece series welding device (100); the transfer device is used for transferring the battery piece loaded with the welding band group to a welding station and/or transferring the battery piece serial welding device (100) to the welding station;

the battery piece serial welding device (100) is used for uniformly radiating VCSEL laser to the battery piece so as to realize the welding of the main grid bonding pad and the welding strip on the surface of the battery piece.

2. The battery piece series welding system according to claim 1, wherein the battery piece series welding device (100) comprises a heating module (10), the heating module (10) comprises a heat sink (1) and a plurality of VCSEL laser chips (2), the plurality of VCSEL laser chips (2) are arranged on the heat sink (1) in an ordered array, and positive and negative connection terminals are arranged on the heat sink (1) and used for being connected with a power supply to electrify the VCSEL laser chips (2).

3. The battery cell series welding system according to claim 2, wherein the battery cell series welding device (100) further comprises a mounting box (3), the heating module (10) is mounted on the mounting box (3) or a plurality of the heating modules (10) are mutually spliced on the mounting box (3) so that a plurality of the VCSEL laser chips (2) form a light emitting and radiating surface having the battery cell irradiation area.

4. A series welding system for battery pieces according to claim 3, wherein a light transmission opening is formed in the mounting box (3), a plurality of heating modules (10) are mounted in the mounting box (3), laser light of the VCSEL laser chip (2) irradiates the battery pieces through the light transmission opening, protective glass (5) is mounted at the position of the light transmission opening, and the protective glass (5) is used for protecting the VCSEL laser chip (2).

5. The series welding system for battery pieces according to claim 4, wherein the two sides of the protective glass (5) are plated with an antireflection film, and the antireflection film is used for selectively filtering laser light with the wavelength of 920-960 nm.

6. A series welding system for battery pieces according to claim 3, wherein a heat conducting plate (4) is mounted on the mounting box (3), the heat conducting plate (4) is attached to one side of the heat sinks (1) away from the VCSEL laser chip (2), and a cooling mechanism for cooling the heat conducting plate (4) is further arranged in the mounting box (3).

7. The battery piece series welding system according to claim 6, wherein a cooling water channel (41) is arranged in the heat conducting plate (4), and the cooling mechanism comprises a water pipe connector fixedly arranged at the inlet and outlet positions of the cooling water channel (41).

8. The battery piece series welding system according to claim 7, wherein a first sensor is arranged on the heat conducting plate (4), and the first sensor is used for detecting the working temperature of the heat conducting plate (4).

9. The battery piece series welding system according to claim 8, wherein the cooling water paths (41) extend along the length direction of the heating modules (10) and realize full coverage of all the heating modules (10) in the width direction thereof, and the first sensors are uniformly distributed on the heat conducting plate (4) corresponding to the positions of each cooling water path (41) in the length direction of the cooling water paths (41).

10. A battery piece series welding system according to claim 3, characterized in that a second sensor for detecting the temperature of the battery piece is arranged on the mounting box (3), and the second sensor is a non-contact infrared temperature measuring sensor.

11. The battery cell series welding system according to any of claims 2-10, characterized in that the output operating wavelength of the VCSEL laser chip (2) employed on the heat sink (1) is one or a combination of more than one of 808nm, 850nm, 905nm, 940nm and 980 nm.