Laser welding method, welding device and readable medium
By using metal laminates instead of the battery case, adjusting the focal length of the laser welding device, determining the optimal focal length and performing laser welding, the problem of inaccurate focal length debugging in the existing technology is solved, and more efficient welding effect and cost savings are achieved.
Patent Information
- Application Number
- CN202510306063.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2022-08-30
- Publication Date
- 2025-05-06
AI Technical Summary
The existing laser welding technology cannot accurately control the focal length during debugging, resulting in inconsistent welding effects, requiring destructive testing, wasting materials and increasing costs.
Metal laminates are used instead of the actual battery shell, and laser light is emitted to the laminate by adjusting the focal length of the laser welding device, the melt pool depth of the welding joint position is obtained, the optimal focal length is determined and laser welding is performed.
It reduces the cost of raw materials, saves inspection costs, shortens the inspection feedback time, and improves the accuracy and efficiency of welding effects.
Smart Images
Figure CN119927425A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of battery technology, and in particular to a laser welding method, a welding device and a readable medium. Background Art
[0002] At present, cars have become a common means of transportation for more and more people. Lithium batteries are a clean energy source that can provide power for cars. Lithium batteries have the advantages of long life, practical safety, large capacity, small size, and light weight, and are widely used in many fields. As a new energy source, lithium-ion batteries are widely used in our lives, and shell batteries have become one of the most widely used battery models among lithium-ion batteries because of their safety advantages. During the production process of batteries with different types of shells, the shells and cover plates are sealed by laser welding. When the laser welder is debugged during production change, the actual welding effect on the object is manually observed. The focus height is manually adjusted through the height mechanical adjustment mechanism. The welding is repeated and observed, and finally it can only be roughly confirmed whether the focal height is adjusted appropriately. In order to ensure the complete airtightness in the shells of different types and the tensile strength requirements of the battery, the molten pool depth and the effective welding area at the weld point position are debugged when the laser welder is welded. The material needs to be subjected to destructive slicing / grinding / corrosion metallographic testing to inspect the welding effect and to confirm whether the focal length debugging in the height direction is in place. The material needs to be scrapped. Every laser welder wastes material every time it is changed, which wastes manpower and material resources, and increases the time, manpower and material costs of materials and inspection.
[0003] The current focal depth and height cannot be accurate enough, the welding effect cannot be quantified and unified, the adjustment process is complicated, actual welding is required, and test materials are consumed. Therefore, a welding process suitable for a new method of checking whether the focal length has changed is needed.
[0004] Therefore, there is an urgent need to provide a new laser welding solution to improve the above problems. Summary of the invention
[0005] The purpose of the present invention is to provide a laser welding method for predicting the focal length position by using metal stacks instead of the actual shell, so as to more conveniently and quickly determine the optimal laser welding focal length of laser welding and improve the laser welding effect.
[0006] In a first aspect, an embodiment of the present invention provides a laser welding method, the method comprising: providing N layers of metal sheets of the same material as a battery shell to be welded, the sum of the thicknesses of the N layers of metal sheets being equal to the thickness of the battery shell; using a clamping device to stack and clamp the N layers of metal sheets, and laying the compressed N layers of metal sheets on the upper layer of a thin plate, the thickness of the thin plate being the same as the thickness of a battery cover to be welded, and the material of the thin plate being the same as the material of the battery cover to be welded; adjusting the focal length between the emitting end of the laser welder and the surface of the N layers of metal sheets according to a first offset λ times, and controlling the laser welder to use different focal lengths to weld the N layers of metal sheets The laser is emitted at K welding point positions to perform laser welding on the battery shell and the battery cover plate, wherein the focal length is the vertical distance between the surface of the N-layer metal sheet and the emission end of the laser welder; after the laser welding is completed, the number of metal sheet layers respectively penetrated at the K different welding point positions is obtained by peeling off the welded back side of the N-layer metal sheet; and the molten pool depths of the K welding point positions are determined according to the number of metal sheet layers penetrated at the K welding point positions; the optimal laser welding focal length of laser welding is determined according to the focal length corresponding to the welding point position with the deepest molten pool depth; and the battery shell and battery cover plate to be welded are laser welded using the optimal laser welding focal length.
[0007] The beneficial effect of the laser welding method provided by the embodiment of the present invention is that in the traditional laser welding scheme, the shell and the cover plate of different models of shell batteries are sealed by laser welding during the production process. When the production model is changed, the machine is debugged. In order to ensure the complete airtightness in the shell of different models and the tensile strength of the battery, the molten pool depth and effective welding area of the welding point position at the debugging machine welding need to be destructively sliced / grinded / corroded by metallographic testing to check the welding effect, to confirm the focal length change in the height direction, and to scrap the material. Each machine needs to scrap the material every time it is changed, which wastes manpower and material resources and increases the time, manpower and material costs of materials and inspection. Compared with the traditional laser welding scheme, the present invention uses metal stacking to replace the actual shell to judge the focal length, which reduces the raw material cost of the shell. At the same time, the stripping observation method is used instead of metallographic inspection to save the inspection cost, and the time cycle from metallographic inspection feedback to machine adjustment is shortened. It is more convenient and quick to feedback the position of the focal length of the laser machine, and improve the laser welding effect.
[0008] In a possible implementation, before determining the optimal laser welding focal length of laser welding according to the focal length corresponding to the weld point position with the deepest molten pool depth, the method further includes: adjusting the focal length between the emitting end of the laser welder and the surface of the N-layer metal sheet M times according to the second offset, sequentially controlling the laser welder to emit lasers to M different weld point positions of the N-layer metal sheet according to the adjusted focal length, wherein the second offset is less than the first offset; after the laser welding is completed, obtaining the number of metal sheet layers penetrated at the M different weld point positions by peeling off the welded back surface of the N-layer metal sheet; and determining the molten pool depth at the weld point position according to the number of metal sheet layers penetrated at the weld point position. In this implementation, by repeatedly performing the above steps using a fine-grained second offset, the focal length corresponding to the weld point position with the deepest molten pool depth can be determined more accurately.
[0009] In a possible implementation, the number of metal sheet layers penetrated at the M different welding point positions is obtained by peeling off the welding back side of the N layers of metal sheets; and the molten pool depth at the welding point position is determined according to the number of metal sheet layers penetrated at the welding point position, and then it also includes: adjusting the focal length between the emission end of the laser welder and the surface of the N layers of metal sheets L times according to the third offset, and sequentially controlling the laser welder to emit lasers to the L different welding point positions of the N layers of metal sheets according to the adjusted focal length, and the third offset is less than the second offset; after the laser welding is completed, the number of metal sheet layers penetrated at the L different welding point positions is obtained by peeling off the welding back side of the N layers of metal sheets; and the molten pool depth at the welding point position is determined according to the number of metal sheet layers penetrated at the welding point position. In this implementation, in this implementation, by repeating the above steps with a finer-grained third offset, the focal length corresponding to the welding point position with the deepest molten pool depth can be determined more accurately.
[0010] In another possible implementation, the optimal laser welding focal length for laser welding is determined according to the focal length corresponding to the weld point position with the deepest molten pool depth, including: when the molten pool depth at the weld point position changes from shallow to deep and then to shallow again, determining the focal length corresponding to the weld point position with the molten pool depth as the optimal laser welding focal length for laser welding. This solution can accurately determine the optimal laser welding focal length by analyzing the change in the molten pool depth at the weld point position. BRIEF DESCRIPTION OF THE DRAWINGS
[0011] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0012] Figure 1A schematic diagram of the effect of a laser welding method provided by the prior art;
[0013] Figure 2 A schematic diagram of a laser welding method provided by an embodiment of the present invention;
[0014] Figure 3 A schematic diagram of laser welding using a laminated sheet and a peeling observation method is provided for an embodiment of the present invention;
[0015] Figure 4 A schematic diagram of welding melting point depths at five welding positions provided in an embodiment of the present invention. DETAILED DESCRIPTION
[0016] At present, in the production process of traditional batteries with different shells, the shell and cover are sealed by laser welding. When the shell of the battery is replaced during the production process, the machine needs to be re-adjusted. In order to ensure the complete airtightness of the shells of different models and the tensile strength of the battery, the molten pool depth and effective welding area of the welding point position of the machine need to be repeatedly adjusted. Figure 1 As shown in (a), in the conventional method, the laser welder 03 emits laser to the battery housing 02 to weld the battery housing 02 and the battery cover 01 together, in order to determine the optimal welding focal length. Figure 1 As shown in (b), the traditional method is to perform destructive slicing / grinding / corrosion metallographic testing on the material after welding to check the welding effect, so as to confirm the focal length change in the height direction. This results in the need to scrap the material every time the machine is scrapped, which wastes manpower and material resources and increases the time, manpower and material costs of materials and inspection.
[0017] In order to solve this problem, the present invention provides a laser welding method, which uses metal stacks to replace the actual shell to predict the focal length position, so as to more conveniently and quickly determine the optimal laser welding focal length of laser welding and improve the laser welding effect.
[0018] The technical solutions in the embodiments of the present invention are described below in conjunction with the accompanying drawings in the embodiments of the present invention. Among them, in the description of the embodiments of the present invention, the terms used in the following embodiments are only for the purpose of describing specific embodiments, and are not intended to be used as limitations on the present application. As used in the specification and the appended claims of the present application, the singular expressions "a", "said", "above", "the" and "this" are intended to also include expressions such as "one or more", unless there is a clear contrary indication in the context. It should also be understood that in the following embodiments of the present application, "at least one", "one or more" refer to one or more than two (including two). The term "and / or" is used to describe the association relationship of associated objects, indicating that three relationships can exist; for example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the objects associated before and after are in an "or" relationship.
[0019] References to "one embodiment" or "some embodiments" etc. described in this specification mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Thus, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways. The term "connection" includes direct connection and indirect connection, unless otherwise specified. "First" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated.
[0020] In the embodiments of the present invention, words such as "exemplarily" or "for example" are used to indicate examples, illustrations or explanations. Any embodiment or design described as "exemplarily" or "for example" in the embodiments of the present invention should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplarily" or "for example" is intended to present related concepts in a specific way.
[0021] like Figure 2 As shown, the present invention provides a laser welding method, the method comprising:
[0022] S201, providing N layers of metal sheets made of the same material as the battery casing to be welded, wherein the sum of the thicknesses of the N layers of metal sheets is equal to the thickness of the battery casing.
[0023] S202, using a pressing device to stack and press the N layers of metal sheets, and laying the pressed N layers of metal sheets on the upper layer of a thin plate, the thickness of the thin plate is the same as the thickness of the battery cover to be welded, and the material of the thin plate is the same as the material of the battery cover to be welded.
[0024] S203, adjusting the focal length between the emitting end of the laser welder and the surface of the N-layer metal sheet according to the first offset λ times, controlling the laser welder to emit lasers to K welding points of the N-layer metal sheet with different focal lengths, so as to perform laser welding on the battery shell and the battery cover.
[0025] S204, after the laser welding is completed, the number of metal sheet layers penetrated at the K different welding point positions is obtained by peeling off the welded back side of the N layers of metal sheet; and the molten pool depths of the K welding point positions are determined according to the number of metal sheet layers penetrated at the K welding point positions.
[0026] S205, determining the optimal laser welding focal length for laser welding according to the focal length corresponding to the welding point position with the deepest molten pool depth.
[0027] S206, laser welding the battery shell and battery cover to be welded using the optimal laser welding focal length.
[0028] In a possible implementation, before determining the optimal laser welding focal length of laser welding according to the focal length corresponding to the weld point position with the deepest molten pool depth, the method further includes: adjusting the focal length between the emitting end of the laser welder and the surface of the N-layer metal sheet M times according to the second offset, sequentially controlling the laser welder to emit lasers to M different weld point positions of the N-layer metal sheet according to the adjusted focal length, wherein the second offset is less than the first offset; after the laser welding is completed, obtaining the number of metal sheet layers penetrated at the M different weld point positions by peeling off the welded back surface of the N-layer metal sheet; and determining the molten pool depth at the weld point position according to the number of metal sheet layers penetrated at the weld point position. In this implementation, by repeatedly performing the above steps using a fine-grained second offset, the focal length corresponding to the weld point position with the deepest molten pool depth can be determined more accurately.
[0029] In a possible implementation, the number of metal sheet layers penetrated at the M different welding point positions is obtained by peeling off the welding back side of the N layers of metal sheets; and the molten pool depth at the welding point position is determined according to the number of metal sheet layers penetrated at the welding point position, and then it also includes: adjusting the focal length between the emission end of the laser welder and the surface of the N layers of metal sheets L times according to the third offset, and controlling the laser welder to emit lasers to the L different welding point positions of the N layers of metal sheets in sequence according to the adjusted focal length, and the third offset is less than the second offset; after the laser welding is completed, the number of metal sheet layers penetrated at the L different welding point positions is obtained by peeling off the welding back side of the N layers of metal sheets; and the molten pool depth at the welding point position is determined according to the number of metal sheet layers penetrated at the welding point position. In this implementation, in this implementation, by repeating the above steps with a finer-grained third offset, the focal length corresponding to the welding point position with the deepest molten pool depth can be determined more accurately, and λ, N, M, L, and K are positive integers.
[0030] In another possible implementation, the optimal laser welding focal length for laser welding is determined according to the focal length corresponding to the weld point position with the deepest molten pool depth, including: when the molten pool depth at the weld point position changes from shallow to deep and then to shallow again, determining the focal length corresponding to the weld point position with the molten pool depth as the optimal laser welding focal length for laser welding. This solution can accurately determine the optimal laser welding focal length by analyzing the change in the molten pool depth at the weld point position.
[0031] Combination Figure 3 For example, by simulating the actual welding state, Figure 3 The four-layer metal sheet 04 shown replaces the battery shell 02 of the same material and thickness. The four-layer metal sheet is pressed by a pressing device and laid on a 1mm thick thin plate 03 to make the contact surface gapless. The thin plate 03 replaces the battery cover 01. The laser welder 03 uses different focal lengths to emit lasers to the five welding points of the four-layer metal sheet, so that the upper surface of the four-layer metal sheet is placed below the machine close to the focal position. The actual shell welding energy is used to increase the focal height according to a certain gradient of 0.5mm, and weld in different welding positions in turn. Figure 3 It can be seen that the five welding positions include welding position A, welding position B, welding position C, welding position D and welding position E. After the welding is completed, the stack is removed and peeled off from the bottom to see the position where the laser reaches the bottom of the molten pool to determine the depth of the molten pool, as shown in Table 1. Until the depth of the molten pool changes from shallow to deep and then to shallow, it can be determined that the deepest position is the position closest to the focal length of the laser welding.
[0032]
[0033]
[0034] Table 1
[0035] Assuming that the depth of the above welding position C is still not optimal, you can continue to repeat the above process with a gradient of 0.2mm according to Gradient 2 until you find the deepest position that is closer to the focal length, and then repeat the above process with a gradient of 0.1mm according to Gradient 3 until you find the deepest position that is closest to the focal length. In this way, you can quickly find the focal length in the shortest time using only a stack of thin sheets.
[0036] In summary, in the traditional laser welding scheme, the shell and cover plate of different models of shell batteries are sealed by laser welding during the production process. When the production model is changed, the machine is debugged. In order to ensure the complete airtightness in the shells of different models and the tensile strength of the battery, the molten pool depth and effective welding area of the welding point position at the time of debugging the machine welding need to be tested by destructive slicing / grinding / corrosion metallographic testing of the material to verify the welding effect, to confirm the focal length change in the height direction, and to scrap the material. Each machine needs to scrap the material every time it is changed, which wastes manpower and material resources and increases the time, manpower and material costs of materials and inspection. Compared with the traditional laser welding scheme, the present invention uses metal stacking instead of the actual shell to judge the focal length, which reduces the raw material cost of the shell. At the same time, the stripping observation method is used instead of metallographic inspection to save the inspection cost, and the time cycle from metallographic inspection feedback to machine adjustment is shortened. It is more convenient and quick to feedback the position of the focal length of the laser machine, and improve the laser welding effect.
[0037] Through the description of the above implementation methods, technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above functional modules is used as an example. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device is divided into different functional modules to complete all or part of the functions described above. The specific working process of the system, device and unit described above can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here.
[0038] Each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above integrated unit may be implemented in the form of hardware or in the form of software functional units.
[0039] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the embodiment of the present invention is essentially or part of the contribution to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) or a processor to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as flash memory, mobile hard disk, read-only memory, random access memory, disk or optical disk.
[0040] The above is only a specific implementation of the embodiment of the present invention, but the protection scope of the embodiment of the present invention is not limited thereto. Any changes or substitutions within the technical scope disclosed in the embodiment of the present invention should be included in the protection scope of the embodiment of the present invention. Therefore, the protection scope of the embodiment of the present invention should be based on the protection scope of the claims.
Claims
1. A laser welding method, characterized in that: The method comprises: Adjusting the focal length between the emitting end of the laser welder and the surface of the N-layer metal sheet according to the first offset λ times, so as to control the laser welder to emit laser light to the K welding point positions of the N-layer metal sheet with different focal lengths; Wherein, the N layers of metal sheets are stacked and then pressed by a pressing device, and the pressed N layers of metal sheets are laid on the upper layer of the thin plate; When the molten pool depth at the welding point position changes from shallow to deep and then to shallow again, the optimal laser welding focal length of laser welding is determined according to the focal length corresponding to the welding point position with the deepest molten pool depth; The molten pool depths of the K welding points are determined by obtaining the number of metal sheet layers respectively penetrated at the K welding points and according to the number of metal sheet layers penetrated at the K welding points; Laser welding is performed on the battery housing and the battery cover to be welded using the optimal laser welding focal length; The total thickness of the N-layer metal sheet is the same as the thickness of the battery shell to be welded, and the N-layer metal sheet and the battery shell are made of the same material; Wherein, the thickness of the thin plate is the same as the thickness of the battery cover plate to be welded, and the material of the thin plate is the same as the material of the battery cover plate to be welded.
2. The method according to claim 1, characterized in that When the molten pool depths at the K welding spot positions do not change from shallow to deep and then to shallow, the method further includes: Adjusting the focal length between the emitting end of the laser welder and the surface of the N-layer metal sheet M times according to the second offset, and sequentially controlling the laser welder to emit laser light to M different welding point positions of the N-layer metal sheet according to the adjusted focal length, wherein the second offset is smaller than the first offset; When the molten pool depth at the weld point position changes from shallow to deep and then to shallow again, the optimal laser welding focal length for laser welding is determined according to the focal length corresponding to the weld point position with the deepest molten pool depth; The number of metal sheet layers penetrated at the M different welding point positions is obtained, and the molten pool depths at the M welding point positions are determined according to the number of metal sheet layers penetrated at the M welding point positions.
3. The method according to claim 2, characterized in that When the depth of the molten pool at the welding point position does not change from shallow to deep and then to shallow, the method further includes: adjusting the focal length between the emitting end of the laser welder and the surface of the N-layer metal sheet L times according to the third offset, and sequentially controlling the laser welder to emit laser light to L different welding point positions of the N-layer metal sheet according to the adjusted focal length, wherein the third offset is smaller than the second offset; When the molten pool depth at the welding point position changes from shallow to deep and then to shallow again, the optimal laser welding focal length of laser welding is determined according to the focal length corresponding to the welding point position with the deepest molten pool depth; The number of metal sheet layers penetrated at the L different welding point positions is obtained, and the molten pool depths at the L welding point positions are determined according to the number of metal sheet layers penetrated at the L welding point positions.
4. The method according to any one of claims 1 to 3, characterized in that: The N layers of metal sheets are stacked and pressed by a pressing device, and the pressed N layers of metal sheets are laid on the upper layer of the thin plate, including: The N layers of metal sheets are stacked and compacted by a compacting device, and the compacted N layers of metal sheets are laid on the upper layer of the thin plate so that there is no gap on their contact surfaces.
5. The method according to claim 1, characterized in that By obtaining the number of metal sheet layers respectively penetrated at the K welding point positions, including: The number of metal sheet layers penetrated respectively at the K welding point positions is obtained by peeling off the welded back surfaces of the N layers of metal sheets.
6. A welding device, characterized in that: The device is used to complete the method according to any one of claims 1 to 5.
7. A readable medium, characterized in that: It stores a computer program executable by an electronic device, and when the computer program runs on the electronic device, the electronic device executes the method according to any one of claims 1 to 5.