Laser flight welding device and welding method for narrow battery cell

Abstract

The invention discloses a laser flying welding device and a welding method for a narrow battery cell, relates to the technical field of battery cell laser welding, and is adaptive to a small pole space structure to improve the pressing precision. The pressing mechanism can still stably implement welding and positioning in a compact structure in which the distance between poles is less than 1mm and the width of a battery cell is not more than 30mm; the beat efficiency is improved, and the welding continuity is improved: a designed double-row pressing cooperation mechanism realizes continuous operation of a laser welding head through A / B side alternate pressing and welding scheduling, so that the operation efficiency of a production line is effectively improved, and the requirements of a high-beat automatic production line are met; on the premise of ensuring the stability of the welding quality, the welding rhythm, the pressing adaptability and the welding spot consistency are effectively improved, the overall process window is wider, the process control is more stable, the welding problem of the narrow-spacing battery cell pole columns is solved, and the narrow-spacing battery cell pole column welding device has remarkable production line adaptability, practical popularization value and industrialization prospects.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of laser welding of battery cells, in particular to a laser flying welding device and method for narrow battery cells. BACKGROUND

[0002] In the field of battery manufacturing, the welding of battery cells is one of the key processes. The traditional laser welding of Busbar generally uses a spot welding positioning system based on a copper nozzle compression structure. The typical structure consists of a compression module, a blowing dust removal tool jig, a laser scanning head, a control system, and a motion module, etc. The system usually uses a whole row synchronous compression strategy and is suitable for welding tasks with conventional width and spacing. The basic operation process is as follows: the battery cells are arranged neatly on the assembly platform and then transported to the welding station; the copper nozzle compression module compresses the target pole simultaneously; the laser welding head completes the welding of the welding points according to the predetermined trajectory; the compression mechanism is released and moved to the next row to repeat the above process.

[0003] However, for narrow battery cell welding with a width less than 30mm, the traditional technology has significant bottlenecks. First, the positioning accuracy is insufficient and the space interference is serious. To ensure welding quality, the spacing between the battery cell poles and the battery tab is usually controlled within 0.3mm, which requires precise compression positioning by copper nozzle. However, for narrow battery cells, the pole spacing is too narrow, and the traditional side-by-side copper nozzle cannot effectively layout the blowing protection gas and dust removal structure in limited space, which easily causes physical interference and compression blind area, affecting the welding consistency and quality stability. Second, the welding beat is separated, and the device utilization is low. When laser welding multiple rows of battery cell poles, the traditional method needs to complete the "compression-welding-release" cycle for each row of poles in turn. The laser scanning head is in an idle state during the waiting for the compression action to be completed, the welding beat is cut off, which seriously affects the device utilization and overall line efficiency, and it is difficult to meet the requirements of high beat automation production. SUMMARY

[0004] The purpose of the present application is to provide a laser flying welding device and method for narrow battery cells to solve the problems of space interference, beat separation, and narrow process window in the prior art, and to realize efficient and stable welding operation under a compact structure.

[0005] In order to achieve the above object, the present application provides the following technical scheme: a laser flying welding device for narrow battery cells, which is used for laser welding of narrow spacing battery cells, the narrow spacing battery cells include a plurality of battery cells arranged in one or more columns, positive and negative poles are arranged on the top surface of the battery cells near the front and back sides respectively, and the positive and negative poles of adjacent two battery cells are reversely arranged; the positive and negative poles of adjacent two battery cells are welded into one by a gasket; a copper nozzle pressing mechanism is used for synchronously pressing and fixing a plurality of gaskets and a plurality of battery cells; a visual detection part for visual scanning detection is arranged above the copper nozzle pressing mechanism, and a laser welding part for welding the gasket and the battery cell into one is arranged above the copper nozzle pressing mechanism; the copper nozzle pressing mechanism includes a transversely arranged pressing support and a plurality of inverted cone pressing heads arranged on the bottom surface of the pressing support; the number of the inverted cone pressing heads is half of the number of the battery cells, and a laser beam inlet is arranged at the center of the inverted cone pressing head; after the gasket and the battery cell are positioned and pressed, the laser beam can pass through the laser beam inlet to weld the pole of the bottom gasket; a downward inclined gas passage is arranged in the inside of the inverted cone pressing head at the middle position of the laser beam inlet, the gas passage communicates with the welding area at the bottom of the pressing nozzle through the laser beam inlet, so that the protective gas can efficiently cover the welding pool to prevent oxidation reaction in the welding process; one end of the gas passage close to the outside is provided with a protective gas inlet which is vertically upward and arranged at the top end; negative pressure dust suction passages are arranged on both sides of the bottom of the inverted cone pressing head; the visual detection part is arranged above the column of battery cells and the copper nozzle pressing mechanism, and is used for visually detecting whether the position of the battery cell and the gasket pressed by the copper nozzle pressing mechanism meets the welding requirement; the laser welding part includes a laser generator arranged through a support, the laser generator is connected with a laser galvanometer, and the laser generator and the laser galvanometer can move axially through a moving slide and a moving motor.

[0006] Preferably, the electrodes of each column of battery cells are divided into A and B sides, A represents the front side pole welding area, and B represents the rear side pole welding area; a plurality of battery cells are divided into sequence ① and sequence ② according to the actual arrangement mode, wherein sequence ① represents odd column battery cells, and sequence ② represents even column battery cells, and the sequence number is used to distinguish the pressing area of the alternating welding battery cell pole column.

[0007] Preferably, the width of a single battery cell is ≤30 mm, and the spacing between the positive and negative poles of adjacent two battery cells is ≤30 mm.

[0008] Preferably, the length of the gasket is the width of two battery cells, and the gasket is used to connect the mutually close positive and negative poles of adjacent two battery cells into one.

[0009] Preferably, the channel size of the laser beam entrance is slightly larger than the actual weld width.

[0010] According to the laser flying welding device for narrow battery core of claim 5, the size of the inverted cone pressing head is the size of two or more pole working positions, thereby ensuring the pressing contact area of the copper nozzle and avoiding the space interference in the pressing and welding processes.

[0011] The welding method using the above-mentioned laser flying welding device for narrow battery core is mainly as follows for the laser welding operation of the above-mentioned narrow-pitch battery core:

[0012] Step one: the A-side copper nozzle pressing mechanism is positioned to the A-side to-be-welded area through the visual detection unit, the position of the A-side copper nozzle pressing mechanism is adjusted, the copper nozzle of the pressing mechanism is positioned to the odd-numbered column (① sequence) of the A-side, and the laser head performs the welding operation on the pressing area; at the same time, the B-side pressing mechanism is positioned to the B-side to-be-welded area, and the B-side pressing mechanism is positioned to the odd-numbered column of the B-side.

[0013] Step two: the A-side odd-numbered column welding is completed, the B-side odd-numbered column pressing action is completed synchronously, the welding head is moved to the position of the B-side odd-numbered column for welding; at the same time, the A-side positioning pressing mechanism is adjusted to the even-numbered column (② sequence) of the A-side for pressing.

[0014] Step three: the B-side odd-numbered column welding is completed, the A-side even-numbered column positioning pressing action is completed, the welding head is moved to the position of the A-side even-numbered column for welding; at the same time, the B-side positioning pressing mechanism is adjusted to the B-side even-numbered column.

[0015] Step four: the A-side even-numbered column welding is completed, the A-side welding task is completed, the welding head is moved to the position of the B-side even-numbered column for welding, and the welding task of the single-row battery core is completed after the completion of the process, and the welding of the multiple-row battery core tabs is realized through multiple cycles.

[0016] Preferably, when welding multiple columns of battery cores, double-row copper nozzle pressing mechanisms can be used, which are respectively located on both sides of the battery core, so that the pressing and welding processes can be alternately and concurrently performed. When the pressing and welding of the current side are completed, the pressing preparation of the other side is synchronously performed, the laser welding process is continuously operated without waiting, the welding continuity and the beat efficiency are effectively improved, the laser head is prevented from being idle or the beat from being interrupted due to process waiting, and the application is suitable for the production of narrow battery core modules with limited space but strict beat requirements.

[0017] Compared with the prior art, the application has the following beneficial effects:

[0018] 1. The application is suitable for small pole column spacing structure, which improves the pressing accuracy: staggered pole column pressing strategy is adopted, combined with inverted cone copper nozzle design, so that the pressing mechanism can still be stably implemented in the compact structure with pole column spacing less than 1mm and cell width not more than 30mm. Compared with the traditional overall pressing mode, the copper nozzle arrangement interference risk is significantly reduced, and the positioning accuracy and consistency of the pressing area are effectively improved;

[0019] 2. The beat efficiency is improved, and the welding continuity is improved: the designed double-row pressing cooperation mechanism realizes the continuous operation of the laser welding head through A / B side alternating pressing and welding scheduling. Compared with the traditional "pressing-welding-release" serial operation mode, the scheme can reduce more than 20% of the beat air gap time, effectively improve the production line operation efficiency, and meet the demand of high beat automatic production line;

[0020] 3. The device structure is highly integrated, and the space utilization rate is optimized: the staggered pressing and inverted cone structure design provides more arrangement redundancy for the copper nozzle mechanism, reasonably integrates the laser light path, protection gas channel and positioning unit, so that the whole machine structure is more compact and the functional integration degree is higher, which is beneficial to realize modularization and standardization design, and improve the engineering realizability;

[0021] The application effectively improves the welding beat, pressing adaptability and weld consistency under the premise of ensuring the stability of the welding quality, and has a wider overall process window and more stable process control, solves the problem of narrow spacing cell pole welding, and has significant production line adaptability, practical popularization value and industrialization prospect. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 It is a schematic diagram of laser welding of the application;

[0023] Figure 2 It is a schematic diagram of narrow spacing cell arrangement;

[0024] Figure 3 It is a sectional view of the copper nozzle pressing mechanism;

[0025] Figure 4 It is a schematic diagram of double-row copper nozzle pressing mechanism pressing cell;

[0026] Figure 5 It is a schematic diagram of odd column welding area;

[0027] Figure 6 It is a schematic diagram of even column welding area;

[0028] In the figure: cell-1, positive pole-11, negative pole-12, tab-2, copper nozzle pressing mechanism-3, pressing support-31, inverted cone pressing head-32, laser beam inlet-33, gas path channel-34, protection gas inlet-35, negative pressure dust collection channel-36, laser welding part-4, laser galvanometer-41. DETAILED DESCRIPTION

[0029] In order for those skilled in the art to better understand the technical solutions of the present application, the technical solutions in the embodiments of the present application are described clearly and completely below in combination with the drawings and specific embodiments.

[0030] Please refer to Figures 1-6 , Figure 1 is a schematic diagram of laser welding of the present application; Figure 2 is a schematic diagram of narrow-pitch cell arrangement of the present application; Figure 3 is a sectional view of a copper nozzle pressing mechanism; Figure 4 is a schematic diagram of double-row copper nozzle pressing mechanism pressing cells; Figure 5 is a schematic diagram of an odd-numbered column welding area; Figure 6 is a schematic diagram of an even-numbered column welding area.

[0031] A narrow-pitch cell includes a plurality of cells 1 arranged in one or more columns, a positive electrode post 11 and a negative electrode post 12 are respectively arranged on the top surface of the cell 1 near the front and rear sides thereof, and the positive electrode posts 11 and the negative electrode posts 12 of adjacent two cells are reversely arranged; the width of a single cell 1 is ≤30 mm, that is, the distance between the positive electrode posts 11 and the negative electrode posts 12 of adjacent two cells is ≤30 mm, and the positive electrode posts 11 and the negative electrode posts 12 of the adjacent two cells 1 close to each other are welded into one body by a tab 2; the electrodes of each column of cells 1 arranged in a column are divided into A and B sides, A represents a front-side electrode post welding area, and B represents a rear-side electrode post welding area; the plurality of cells 1 are divided into sequence ① and sequence ② according to the actual arrangement mode, wherein the sequence ① represents an odd-numbered column of cells, and the sequence ② represents an even-numbered column of cells, and the sequence number is used to distinguish the pressing areas of the alternatingly welded electrode post columns.

[0032] The length of the tab 2 is the width of two cells 1, and the tab 2 is used to connect the positive electrode posts 11 and the negative electrode posts 12 of the adjacent two cells 1 close to each other into one body.

[0033] A welding device for laser welding of the above-mentioned narrow-pitch cell 1 includes a copper nozzle pressing mechanism 3 for synchronously pressing and fixing a plurality of tabs 2 and a plurality of cells 1, a visual detection part above the copper nozzle pressing mechanism 3 for visual scanning detection, and a laser welding part 4 for welding the tab 2 and the cell 1 into one body; before welding, all the cells 1 need to be arranged in a designated position, and then pressed by the copper nozzle pressing mechanism 3, and then positioned by visual scanning of the visual detection part, and then welded by the laser welding part according to a predetermined track.

[0034] The copper nozzle pressing mechanism 3 includes a transversely arranged pressing support 31, a plurality of inverted taper pressing heads 32 are uniformly arranged on the bottom surface of the pressing support 31, the number of the inverted taper pressing heads 32 is half of the number of the battery cells 1, a laser beam inlet 33 is arranged at the center of the inverted taper pressing head 32, and the laser beam inlet 33 is used for the passage of the welding laser beam, after the positioning and pressing of the tab 2 and the battery cell 1 during welding, the laser beam can pass through the laser beam inlet 33 to weld the pole of the bottom tab 2, the channel size of the laser beam inlet 33 is slightly larger than the actual weld width, which ensures that the laser beam can still completely cover the weld area within the positioning error range; a downward inclined gas passage 34 is arranged inside the inverted taper pressing head 32 at the middle position of the laser beam inlet 33, the gas passage 34 communicates with the welding area at the bottom of the pressing nozzle through the laser beam inlet 33, thereby ensuring that the protective gas can efficiently cover the welding pool to prevent oxidation during welding, one end of the gas passage 34 close to the outside is provided with a protective gas inlet 35 which is vertically upward and arranged at the top, negative pressure dust suction passages 36 are arranged on both sides of the bottom of the inverted taper pressing head 32, which facilitates the timely discharge of spatter and metal vapor during laser welding, and reduces the risk of pollution and residue; in order to match the welding of narrow-pitch battery cell poles, the size of the inverted taper pressing head 32 is the size of two or more pole working positions, thereby ensuring the pressing contact area of the copper nozzle and avoiding the problem of space interference during pressing and welding.

[0035] When the copper nozzle pressing mechanism 3 is used to press the battery cell 1, the two sides of the battery cell 1 are pressed in turn, thereby ensuring the continuity of the beat.

[0036] The visual detection device is arranged above the column of battery cells 1 and the copper nozzle pressing mechanism 3, and is used for visually detecting the position of the battery cell 1 and the tab 2 pressed by the copper nozzle pressing mechanism 3, and judging whether the welding requirement is met.

[0037] The laser welding part 4 includes a laser generator arranged through a support, the laser generator is connected with a laser galvanometer 41, and the laser generator and the laser galvanometer 41 can move axially through a moving slide and a moving motor drive; the laser galvanometer 41 is arranged above the column of battery cells 1 and the copper nozzle pressing mechanism 3, and is used for laser welding operation on the battery cell 1 and the tab 2 pressed by the copper nozzle pressing mechanism 3 which has been visually confirmed.

[0038] For the above-mentioned laser welding operation of the column of narrow-pitch battery cells, the pressing and welding process mainly includes:

[0039] Step one: positioning to the A side to be welded area through visual detection, adjusting the position of the A side copper nozzle compression mechanism 3, so that the copper nozzle of the compression mechanism is in the odd column (① sequence) of the A side, and the laser head performs welding operation on the compression area; at the same time, the B side compression mechanism is placed in the B side to be welded area, and the B side compression mechanism is positioned to the B side odd column.

[0040] Step two: the A side odd column welding is completed, the B side odd column compression action is completed synchronously, the welding head moves to the B side odd column position for welding; at the same time, the A side positioning compression mechanism adjusts the position to the A side even column (② sequence) for compression.

[0041] Step three: the B side odd column welding is completed, the A side even column positioning compression action is completed, the welding head moves to the A side even column position for welding; at the same time, the B side positioning compression mechanism adjusts to the B side even column.

[0042] Step four: the A side even column welding is completed, the A side completes all the welding tasks, the welding head moves to the B side even column position for welding, and after the completion of the process, all the welding tasks of the single row battery cell are completed, and the welding of multiple rows of battery cell tabs is realized through multiple cycles.

[0043] In addition, the above welding method can also be used for multiple column battery cell welding operation, and double row copper nozzle compression mechanism 3 can be used when welding multiple column battery cells, which are respectively located on both sides of the battery cell, so that the compression and welding process can be alternately parallel. When the compression and welding of the current side are completed, the compression preparation of the other side is synchronized to realize the continuous operation of the laser welding process without waiting, effectively improve the welding continuity and beat efficiency, avoid the idle or beat interruption of the laser head caused by process waiting, and be suitable for narrow battery cell module production scene with limited space but strict beat requirement.

[0044] The present application realizes accurate compression through the structure optimization of the compression nozzle. The bottom contact area of the conical compression mechanism is strictly matched with the to-be-welded area of the pole, and the upper part is gradually expanded to form an integrated gas guide area and a light channel window, and the size of the light channel window is larger than the actual size of the weld, which can effectively guide the laser beam and the protective gas to accurately reach the to-be-welded position in the limited space. The inverted cone design makes multiple compression nozzles not interfere with each other under compact arrangement, which is especially suitable for the battery cell structure with narrow spacing and multiple rows distribution.

[0045] The pressing-welding process is coordinated to ensure synchronization and beat continuity. On the basis of the cross pressing strategy, the matched welding process is coordinated to work, the beat is optimized, in the first period, the front side odd column pole is pressed and welded, during the welding process, the other group of copper nozzle presses the rear side odd column; in the second period, the laser welds the rear side odd column, and the front side even column is pressed synchronously; in the third period, the laser welds the front side even column, and the rear side even column is pressed synchronously. In the fourth period, the laser welds the rear side even column, and all the welding tasks are completed to enter the next welding task. The scheme realizes the parallel scheduling of the pressing action and the welding action in time, greatly shortens the beat intermittent time, and fully gives play to the efficiency advantage of the flying welding system.

[0046] In summary, the application effectively solves the key problems such as space interference, beat interruption and unstable welding of the traditional laser welding process in the application of narrow spacing battery through the introduction of the staggered pressing strategy, the inverted conical copper nozzle structure design and the double-row cooperative scheduling mechanism. The method has strong engineering adaptability and popularization value, and is especially suitable for the welding scene of high-density and narrow-width battery modules.

[0047] Although the embodiments of the present application have been shown and described, it is apparent that the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, it can be understood by those skilled in the art that all other embodiments obtained by various changes, modifications, replacements and variations of the embodiments without creative labor under the condition of not departing from the principles and spirits of the present application, belong to the protection scope of the present application.

Claims

1. A laser flying welding device for narrow cell laser welding, which is used for laser welding of a column of narrow pitch cells, the column of narrow pitch cells comprising a plurality of cells (1) arranged in one or more columns in sequence, a positive pole post (11) and a negative pole post (12) being respectively arranged on the top surface of the cell (1) near the front and back sides thereof, and the positive pole posts (11) and the negative pole posts (12) of adjacent two cells being reversely arranged; the positive pole posts (11) and the negative pole posts (12) of the adjacent two cells (1) close to each other are welded into one body by a strap (2); characterized in that: The application relates to a copper nozzle pressing mechanism (3) used for synchronously pressing and fixing a plurality of tabs (2) and a plurality of battery cores (1), a visual detection part used for visual scanning detection is arranged above the copper nozzle pressing mechanism (3), and a laser welding part (4) used for welding the tabs (2) and the battery cores (1) into a whole is arranged above the copper nozzle pressing mechanism (3); the copper nozzle pressing mechanism (3) comprises a transversely arranged pressing support (31) and a plurality of inverted taper pressing heads (32) uniformly arranged on the bottom surface of the pressing support (31), the number of the inverted taper pressing heads (32) is half of the number of the battery cores (1), and a laser beam inlet (33) is arranged at the axial center of each inverted taper pressing head (32); after the tabs (2) and the battery cores (1) are positioned and pressed, laser beams can pass through the laser beam inlets (33) to weld the pole columns of the bottom tabs (2); a downwardly inclined air passage (34) is arranged in the interior of the inverted taper pressing head (32) at the middle position of the laser beam inlet (33), the air passage (34) communicates with the welding area at the bottom of the pressing nozzle through the laser beam inlet (33), so that the protective gas can efficiently cover the welding molten pool and prevent oxidation reaction in the welding process, one end of the air passage (34) close to the outer side is uniformly provided with a protective gas inlet (35) which vertically upwards and is arranged at the top end, and negative pressure dust suction passages (36) are arranged at the two sides of the bottom of the inverted taper pressing head (32); the visual detection part is arranged above the columned battery cores (1) and the copper nozzle pressing mechanism (3) and is used for visually detecting whether the position of the battery core (1) and the tab (2) pressed by the copper nozzle pressing mechanism (3) meets the welding requirement; the laser welding part (4) comprises a laser generator arranged through a support, the laser generator is connected with a laser vibrating mirror (41), and the laser generator and the laser vibrating mirror (41) can axially move through a moving slide and a moving motor drive; the laser vibrating mirror (41) is arranged above the columned battery cores (1) and the copper nozzle pressing mechanism (3) and is used for laser welding the battery core (1) and the tab (2) pressed by the copper nozzle pressing mechanism (3) which has been visually confirmed.

2. The laser fly welding apparatus of narrow cells of claim 1, wherein: The electrodes of each columned battery core (1) are divided into A and B sides, A represents a front side pole column welding area, and B represents a rear side pole column welding area; a plurality of battery cores (1) are divided into sequence 1 and sequence 2 according to actual arrangement modes, wherein sequence 1 represents odd columned battery cores, and sequence 2 represents even columned battery cores, and the sequence numbers are used for distinguishing the pressing areas of the columned battery core pole columns which are alternately welded.

3. The laser flight welding apparatus for narrow cells of claim 2, wherein: The width of a single battery core (1) is less than or equal to 30 mm, and the spacing between the positive pole columns (11) and the negative pole columns (12) between two adjacent battery cores is less than or equal to 30 mm.

4. The laser flight welding apparatus for narrow cells of claim 3, wherein: The length of the tab (2) is equal to the width of two battery cores (1), and the tab (2) is used for connecting the mutually close positive pole columns (11) and the negative pole columns (12) of two adjacent battery cores (1) into a whole.

5. The laser fly welding apparatus of narrow cells of claim 4, wherein: The channel size of the laser beam inlet (33) is slightly larger than the actual welding seam width.

6. The laser fly welding apparatus of narrow cells of claim 5, wherein: The size of the inverted taper pressing head (32) is equal to the size of two or more pole column working positions, so that the pressing contact area of the copper nozzle is ensured, and space interference in the pressing and welding process is avoided.

7. The method of welding of claim 6, wherein the laser flyer welding apparatus is a narrow cell laser flyer welding apparatus. For the above laser welding operation of the columned narrow pitch battery cell, the pressing and welding process is mainly as follows: Step one: through the visual detection part to position to the A side to be welded area, adjust the position of the A side copper nozzle pressing mechanism (3), so that the copper nozzle of the pressing mechanism is in the odd column of the A side, and the laser head is welded to the pressing area; At the same time, the B side pressing mechanism is placed in the B side to be welded area, and the B side pressing mechanism is positioned to the odd column of the B side. Step two: the A side odd column welding is completed, the B side odd column pressing action is completed synchronously, the welding head moves to the B side odd column position for welding; At the same time, the A side positioning pressing mechanism adjusts the position to the A side even column for pressing. Step three: the B side odd column welding is completed, the A side even column positioning pressing action is completed, the welding head moves to the A side even column position for welding; At the same time, the B side positioning pressing mechanism adjusts to the B side even column. Step four: the A side even column welding is completed, the A side all welding task is completed, the welding head moves to the B side even column position for welding, after this process, the whole welding task of single row battery cell is completed, and the welding of multiple row battery cell tabs is realized through multiple cycles.

8. The laser flight welding apparatus of narrow cells of claim 7, wherein: When welding multiple column battery cells, double row copper nozzle pressing mechanism (3) can be used, which is respectively located on both sides of the battery cell, so that the pressing and welding process can be alternately parallel; When the pressing and welding of the current side are completed, the pressing preparation of the other side is synchronized, realizing the continuous operation of the laser welding process without waiting, effectively improving the welding continuity and beat efficiency, avoiding the idle of the laser head or the interruption of the beat caused by the process waiting, and being suitable for the narrow battery cell module production with limited space but strict beat requirements.

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