Terminal laser welding pressing device and pressing force adjusting method

Abstract

The present application relates to a kind of terminal laser welding pressing device and pressing force adjusting method, and the pressing device includes base, base is equipped with recess, for accommodating backing plate, the top surface of backing plate is equipped with contact portion;Cover plate is set to the top of base, frame is fixed between cover plate and base, frame is equipped with terminal, terminal is equipped with welding portion, the side edge of welding portion extends with the pressure joint portion outward, and opening is equipped on cover plate;Pressing mechanism is movably set in opening, and pressing mechanism is equipped with pressing block, when pressing mechanism is fastened, the surface of pressure joint portion is pressed by pressing block, to press welding portion to adhere to contact portion, both can avoid the warping of welding portion caused by pressure on the top of frame, and can avoid welding area, will not lead to welding area reduction, pressing block can be uniformly forced to different height or warped terminal, to press welding portion on contact portion, guarantee the consistency of the adhesion of welding portion and backing plate, to improve penetration stability, avoid the generation of burst point and false welding, improve welding quality.

Description

Technical Field

[0001] This invention relates to the field of electrical connection technology, and in particular to a terminal laser welding clamping device and a clamping force adjustment method. Background Technology

[0002] Generally, IGBT frame terminals are soldered to the copper layer on the backing plate. Currently, the connection between the copper frame and the backing plate in the industry is mainly brazing, and lead-containing solder is usually used, which cannot meet the needs of the automotive industry. Ultrasonic welding has the risk of causing cracks in the backing plate, while laser welding is a non-contact fusion welding, which has high strength and low impact on ceramic cracks. Therefore, laser welding of the frame and backing plate is a common method in this field.

[0003] Laser welding requires melting the terminal welding area and penetrating to the copper plating on the backing plate to form a molten pool. However, beneath the copper plating on the backing plate is a ceramic layer. When the laser penetrates the ceramic layer, the ceramic vaporizes violently, causing a burst. Therefore, the depth of the molten pool needs to be controlled to about half the thickness of the copper plating on the backing plate. The greater the thickness of the terminal above, the higher the laser welding power required, and the more difficult it is to control the penetration depth. This is because the absorption rate of metal to laser energy varies greatly at room temperature, in the molten state, and when forming a keyhole. At room temperature, copper has an absorption rate of about 5% for infrared lasers, about 25% when molten, and the absorption rate increases sharply to about 90% after forming a keyhole. This change in absorption rate is the root cause of the fluctuation in penetration depth under high power, coupled with heat accumulation, which can easily lead to bursts and cold solder joints. Therefore, laser welding is currently only suitable for situations where the terminal thickness is much smaller than the thickness of the top copper cladding, in order to ensure the consistency of the weld penetration. For top-thick and bottom-thin structures where the terminal thickness is greater than the thickness of the top copper cladding, it has been verified that when there is a 0.1mm gap between the terminal and the backing plate, the rate of blasting or cold solder joints increases dramatically, resulting in poor weld penetration stability and making it unsuitable for mass production.

[0004] Current tooling fixtures typically apply pressure above the frame to make the lower terminals and backing plates fit together. However, due to the frame structure, when the pressure is applied to the upper part of the frame, it inevitably causes slight warping at the front end of the terminals. Furthermore, the backing plates themselves will warp after silver sintering or welding. This pressure application method will result in about 30% of the terminal welding area failing to form a proper bond. In addition, due to the gaps between the terminal backing plates, a large number of burst points will occur, resulting in poor stability.

[0005] Another method is to directly apply pressure to the terminal welding area to make it adhere to the backing plate, but this will cause the laser welding area to be covered, resulting in a reduction in the area of ​​the terminal welding area, which is prone to spalling or poor soldering.

[0006] Since brazing allows for direct clamping of terminals using tooling, and ultrasonic terminal welding itself applies pressure to the terminals, only laser welding requires exposing the terminals. Therefore, the flatness requirements for the frame terminals are not high, which further deteriorates the process stability of laser welding.

[0007] Therefore, it is necessary to design a better terminal welding fixture to solve the above problems. Summary of the Invention

[0008] This invention provides a terminal laser welding clamping device and clamping force adjustment method, which can improve the fit consistency between laser welding frame terminals and backing plates, thereby improving the stability of the weld penetration, avoiding the generation of blasting points and incomplete welds, improving product quality, and is suitable for large-scale engineering operations.

[0009] This invention provides a terminal laser welding clamping device, comprising: The base has a groove for accommodating the liner, and the top surface of the liner has a contact portion; A cover plate is disposed above the base, and a frame is fixed between the cover plate and the base. The frame is provided with a terminal, and the terminal is provided with a welding part. The welding part is located on the contact part, and a pressing part extends outward from the side edge of the welding part. The cover plate is provided with an opening. A clamping mechanism is movably disposed within the opening. The clamping mechanism is provided with a pressure block. When the clamping mechanism is tightened, the pressure block presses against the surface of the crimping part to press the welded part into contact with the contact part.

[0010] In one embodiment, the clamping mechanism includes: Pressure plate, fixed to the cover plate; The pressure block is disposed between the pressure plate and the terminal, and the pressure block has a recessed hole; and A spring is disposed in the recessed hole. The top of the spring is connected to the pressure plate, and the bottom of the spring is connected to the bottom surface of the recessed hole. The spring force presses the pressure block against the pressing part to press the welded part to the contact part.

[0011] In one embodiment, the frame is provided with multiple sets of terminals, and each set of terminals is provided with an independent pressure block. By adjusting the elastic force of the spring, force is applied evenly to the terminals with different heights.

[0012] In one embodiment, the pressure block is connected to a pressure regulating mechanism, which dynamically adjusts the pressure to make the clamping force between the welded part and the contact part reach a preset value.

[0013] In one embodiment, the crimping portion is disposed on both sides of the welding portion, the pressure block is provided with a through groove and pressure columns located on both sides of the through groove, the pressure columns abut against the surface of the crimping portion, the through groove is correspondingly disposed to the welding portion, the pressure plate is provided with a slot, the slot is connected to the through groove to expose the welding portion to the outside for laser welding.

[0014] In one embodiment, the top surface of the crimping portion is flush with the top surface of the welding portion, and the bottom surface of the crimping portion is higher than the bottom surface of the welding portion, so that there is a gap between the crimping portion and the liner.

[0015] In one embodiment, the bottom surface of the cover plate is provided with a stop block, which stops between the terminal and the chip in the middle of the backing plate to prevent soldering spatter from splashing onto the chip.

[0016] In one embodiment, the base is provided with a positioning post and a foolproof post. The positioning post is used to cooperate with the cover plate for positioning, and the foolproof post is used to cooperate with the frame for positioning.

[0017] A method for adjusting the clamping force based on the above-mentioned terminal laser welding clamping device includes: Obtain the contact resistance between the terminal and the contact portion of the liner; Determine whether the contact resistance has reached the set value. If not, adjust the pressure of the pressure block to press the welding part against the contact part until the contact resistance between the terminal and the contact part reaches the preset value.

[0018] In one embodiment, the pressure block has a recessed hole, and a spring is provided in the recessed hole. When the contact resistance is less than a set value, the elastic force of the spring is adjusted so that the contact resistance reaches the set value.

[0019] Compared with the prior art, the advantages of the present invention are that by pressing the pressing part extending from the side edge of the terminal welding part through the pressing mechanism, it can avoid the warping of the welding part caused by applying pressure above the frame, and will not reduce the welding area. Moreover, the pressing mechanism is movably set between the cover plate and the terminal. When the liner warps after sintering or the frame material is inconsistent, resulting in inconsistent terminal heights in different areas, the pressing block can apply force evenly to terminals of different heights or warped terminals to press the welding part onto the contact part, ensuring the consistency of the welding part and the liner, thereby improving the stability of the weld depth, avoiding the generation of blasting points and cold solder joints, improving product quality, and facilitating large-scale mass production. Attached Figure Description

[0020] The invention will now be described in more detail with reference to embodiments and the accompanying drawings.

[0021] Figure 1 This is a perspective view of the terminal laser welding and clamping device of the present invention; Figure 2 This is a top view of the terminal laser welding clamping device of the present invention; Figure 3 This is a perspective sectional view of the terminal laser welding clamping device of the present invention; Figure 4 This is a cross-sectional view of the terminal laser welding clamping device of the present invention; Figure 5 yes Figure 4 A magnified view of a section at point A in the middle; Figure 6 This is a partial cross-sectional view from another perspective of the terminal laser welding clamping device of the present invention; Figure 7 This is a schematic diagram of the structure of the base and liner in the terminal laser welding clamping device of the present invention; Figure 8 This is a schematic diagram of the structure of the base, liner and frame in the terminal laser welding clamping device of the present invention; Figure 9 This is a schematic diagram of the structure of the base, frame and pressure block in the terminal laser welding clamping device of the present invention; Figure 10 This is a schematic diagram of the structure of the cover plate and the back of the frame in the terminal laser welding clamping device of the present invention.

[0022] Figure label: 1. Base; 11. Groove; 12. Positioning pin; 13. Anti-fooling pin; 14. Positioning pin; 15. Threaded hole; 2. Cover plate; 21. Opening; 22. Positioning hole; 23. Stop; 3. Clamping mechanism; 31. Pressure plate; 311. Slot; 32. Pressure block; 321. Concave hole; 322. Through slot; 323. Pressure column; 33. Spring; 4. Backing plate; 41. Contact part; 411. Upper copper layer; 412. Ceramic layer; 413. Lower copper layer; 42. Chip; 5. Frame; 51. Terminal; 511. Welding part; 512. Crimping part; 52. Anti-fooling hole; 53. Pin hole; 6. First bolt; 7. Second bolt. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0024] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0025] Furthermore, the use of terms such as "first" and "second" in this invention is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this invention.

[0026] Laser welding requires melting the terminal welding area and penetrating to the copper plating on the backing plate to form a molten pool. Below the copper plating on the backing plate is a ceramic layer. When the laser penetrates the ceramic layer, the ceramic vaporizes violently, causing a burst. Therefore, the depth of the molten pool needs to be controlled to about half the thickness of the copper plating on the backing plate. The greater the thickness of the upper terminal, the higher the required laser welding power and the more difficult it is to control the penetration depth. This is because the absorption rate of the metal to laser energy varies greatly depending on the temperature, the molten state, and the keyhole formation. At room temperature, copper has an absorption rate of about 5% for infrared lasers, about 25% when molten, and a sharp increase to about 90% after keyhole formation. This change in absorption rate is the root cause of fluctuations in penetration depth under high power, coupled with heat accumulation, which easily leads to bursts and incomplete soldering. Therefore, laser welding is currently only suitable for situations where the terminal thickness is much smaller than the thickness of the top copper cladding, in order to ensure the consistency of the weld penetration. For top-thick and bottom-thin structures where the terminal thickness is greater than the thickness of the top copper cladding, it has been verified that when there is a 0.1mm gap between the terminal and the backing plate, the rate of burst points or incomplete soldering increases dramatically, resulting in poor weld penetration stability and making it unsuitable for mass production.

[0027] This invention provides a terminal laser welding clamping device for pressing the terminal welding part against the upper copper layer on the surface of the backing plate, ensuring the fit of the welding part, and thus ensuring that the penetration depth during laser welding is about half the thickness of the upper copper layer, thereby ensuring welding performance and avoiding spalling or incomplete soldering. This invention is particularly suitable for top-thick and bottom-thin structures where the terminal thickness is greater than the upper copper layer thickness.

[0028] like Figures 1 to 3As shown, the terminal laser welding clamping device of the present invention includes a base 1, a cover plate 2, and a clamping mechanism 3. The base 1 has a groove 11 for accommodating a backing plate 4. The cover plate 2 is disposed above the base 1, and a frame 5 is clamped and fixed between the cover plate 2 and the base 1. The frame 5 is provided with multiple sets of terminals 51. The terminals 51 bend and extend from the edge of the frame 5 toward the center of the base 1. The welding part 511 of the terminal 51 is located on the contact part 41 of the backing plate 4, and the side edge of the welding part 511 of the terminal 51 extends outward to form a clamping part 512. The cover plate 2 has an opening 21 corresponding to the terminal 51. The clamping mechanism 3 is movably disposed in the opening 21. The clamping mechanism 3 includes a pressure block 32. When the clamping mechanism 3 is tightened, the pressure block 32 presses against the surface of the clamping part 512, thereby pressing the welding part 511 to fit against the contact part 41, thereby ensuring the consistency of the fit between the welding part 511 and the backing plate 4, improving the stability of the weld depth, and avoiding the generation of blasting points and incomplete welds.

[0029] The present invention presses the pressure block 32 onto the pressing part 512 on the side edge of the welding part 511, which can avoid the warping of the welding part 511 caused by applying pressure above the frame 5, and does not occupy the welding area, thus not reducing the welding area. When the liner 4 warps after sintering or the frame 5 is inconsistent in material, resulting in inconsistent heights of terminals 51 in different areas, the pressure block 32 can apply force evenly to terminals 51 of different heights or warped terminals to press the welding part 511 tightly onto the contact part 41, thereby ensuring fit and avoiding blasting or incomplete welding, thereby improving the stability of the penetration depth and improving the quality of laser welding.

[0030] like Figure 1 , Figures 4 to 6 As shown, the base 1 has a groove 11 in the middle, which contains a backing plate 4. The backing plate 4 has a chip 42 in the middle, and multiple sets of contact portions 41 are provided on the top surfaces of both ends of the backing plate 4 for contacting the welding portion 511 of the terminal 51 and performing laser welding. The backing plate 4 includes an upper copper layer 411, a ceramic layer 412 located at the bottom of the upper copper layer 411, and a lower copper layer 413 located at the bottom of the ceramic layer 412. The contact portions 41 are located on the surface of the upper copper layer 411 and are used for electrical connection with the terminal 51.

[0031] like Figure 6 and Figure 7As shown, the base 1 is equipped with a positioning post 12 and a foolproof post 13. The positioning post 12 is used to cooperate with the cover plate 2 for positioning, and the foolproof post 13 is used to cooperate with the frame 5 for positioning. It should be noted that the positioning post 12 is located on the top surface of the base 1, and the cover plate 2 has a positioning hole 22 corresponding to the position of the positioning post 12, in which the positioning post 12 is positioned. A foolproof post 13 is provided on one side of the positioning post 12, and a foolproof hole 52 is provided on the frame 5 accordingly. The foolproof post 13 cooperates with the foolproof hole 52 to prevent incorrect installation orientation of the frame 5. The base 1 is also equipped with a positioning pin 14, and the frame 5 has a corresponding pin hole 53. The positioning pin 14 is confined within the pin hole 53, and the frame 5 is confined to the surface of the base 1 by the positioning pin 14, and is then pressed tightly by the cover plate 2. Threaded holes 15 are provided around the base 1.

[0032] In this embodiment, the frame 5 is an IGBT frame 5, and the terminals 51 are provided in four sets. One set of terminals 51 consists of three terminals and is located on one side of the backing plate 4. The other three sets of terminals 51 are arranged side by side on the other side of the backing plate 4. The middle set of terminals 51 consists of three terminals, and the two sets of terminals 51 on both sides each consist of two terminals. The terminals 51 have the same shape. The terminals 51 bend and extend from the edge of the frame 5 towards the middle of the base 1. The welding part 511 is located on the backing plate 4. In this embodiment, the two sides of the width of the welding part 511 extend outward with pressing parts 512 for pressing by the pressing block 32, thereby pressing the welding part 511 tightly onto the contact part 41.

[0033] In this embodiment, crimping portions 512 are provided on both sides of the width of the welding portion 511 of each terminal 51. In other embodiments, the crimping portions 512 may also be provided at the front edge of the welding portion 511. The crimping portions 512 are provided at the side edges of the welding portion 511 for crimping by the pressure block 32 without increasing the size of the terminal 51 body. The shape of the crimping portion 512 may be rectangular or other shapes, and the width of the crimping portion 512 depends on the gap between the terminals 51.

[0034] like Figure 5As shown, in one embodiment, the top surface of the crimping portion 512 is flush with the top surface of the welding portion 511, and the bottom surface of the crimping portion 512 is higher than the bottom surface of the welding portion 511, so that there is a gap between the crimping portion 512 and the surface of the liner plate 4. On the one hand, when the width of the welding portion 511 is wide, applying pressure from both sides of the welding portion 511 will cause the crimping portion 512 to deform downward. If the bottom surface of the crimping portion 512 is flush with the bottom surface of the welding portion 511, a gap will appear below the welding portion 511. However, in this embodiment, the bottom surface of the crimping portion 512 is higher than the bottom surface of the welding portion 511. Even if the crimping portions 512 on both sides are deformed downward under pressure, it will not affect the flatness of the middle welding portion 511, avoid gaps, and ensure that the welding portion 511 and the contact portion 41 are tightly fitted. On the other hand, when the edge of the crimping portion 512 is in the gap between the upper copper layer 411 of the adjacent terminal 51, if the bottom surface of the crimping portion 512 is flush with the bottom surface of the solder portion 511, the crimping portion 512 will press against the edge of the upper copper layer 411 on the other side when pressure is applied, causing deformation of the upper copper layer 411 and damage to the ceramic layer 412. However, the bottom surface of the crimping portion 512 is higher than the bottom surface of the solder portion 511, so that the crimping portion 512 and the upper copper layer 411 at the bottom of the adjacent terminal 51 are kept apart, which can avoid the risk of deformation of the upper copper layer 411 and damage to the ceramic layer 412.

[0035] like Figure 3 and Figure 10 As shown, the cover plate 2 is open in the middle to expose the chip 42. The cover plate 2 has positioning holes 22 that cooperate with the positioning posts 12 of the base 1 for positioning. The cover plate 2 is connected to the base 1 by threaded holes 15 via first bolts 6, fixing the cover plate 2 to the base 1 and simultaneously flattening the frame 5, or allowing the cover plate 2 to flatten the frame 5 by its own weight. An opening 21 is provided on the cover plate 2 corresponding to the terminal 51, penetrating the cover plate 2. In this embodiment, multiple openings 21 are provided, each corresponding to a group of terminals 51. Adjacent openings 21 are separated so that each opening 21 independently accommodates a pressure block 32, applying different pressures to terminal groups of different heights, thereby ensuring consistent overall clamping of the terminals 51 and maintaining a consistent fit. In other embodiments, one terminal 51 may correspond to one pressure block 32.

[0036] In one embodiment, a stop 23 is provided on the bottom surface of the cover plate 2. The stop 23 is positioned between the terminal 51 and the chip 42 to prevent soldering spatter from splashing onto the surface of the chip 42 and causing the chip 42 to be scrapped. In this embodiment, the stop 23 is located at the front edge of the soldering portion 511 of the terminal 51 and stops at the front end of the terminal 51.

[0037] like Figures 3 to 6 and Figure 9As shown, in one embodiment, the clamping mechanism 3 includes a pressure plate 31, a pressure block 32, and a spring 33. The pressure plate 31 is disposed at the opening 21 of the cover plate 2, and the periphery of the pressure plate 31 is fixed to the cover plate 2 by a second bolt 7. The pressure plate 31 has a slot 311, which exposes the welding part 511 of the terminal 51 to the outside for laser welding. The pressure block 32 is disposed between the pressure plate 31 and the terminal 51. The pressure block 32 has a recess 321, and the spring 33 is disposed in the recess 321. The top of the spring 33 is connected to the pressure plate 31, and the bottom of the spring 33 is connected to the bottom surface of the recess 321. The spring force of the spring 33 presses the pressure block 32 against the terminal 51, thereby flattening the terminal 51 and pressing the welding part 511 to the contact part 41.

[0038] In this embodiment, the frame 5 is provided with multiple sets of terminals 51, and each terminal 51 is provided with an independent pressure block 32. By adjusting the elastic force of the spring 33, force is evenly applied to different terminals 51. The spring 33 is provided in the recess 321. The elastic force of the spring 33 causes the pressure block 32 to be elastically and movable between the pressure plate 31 and the terminal 51. When the liner 4 warps after sintering or the material of the frame 5 is inconsistent, resulting in inconsistent heights of the terminals 51 in different areas, the pressure block 32 can evenly transmit pressure to the terminals 51 of different heights or warped terminals under the action of the spring 33, and can flatten and press the terminals 51 of different heights or warped terminals to the liner 4. If a rigid structure is used to transmit pressure or the pressure block 32 is integrated, the pressure of the pressure block 32 will be concentrated on the higher terminals 51, while the lower terminals 51 will not be stressed, resulting in inconsistent pressing force. In this invention, the pressure plate 31 is fixed on the cover plate 2. The pressure of the pressure block 32 depends on the length and stiffness of the spring 33. The stiffness of the spring 33 can be adjusted or the spring 33 can be replaced according to the condition of the terminal 51, so as to apply targeted pressure to different terminals 51 in different areas, so that the clamping force of the welding part 511 of each terminal 51 on the backing plate 4 is consistent, and the fit is consistent.

[0039] In another embodiment, the pressure block 32 is connected to a pressure regulating mechanism, which dynamically adjusts the pressure to ensure that the clamping force between the welding part 511 and the contact part 41 reaches a preset value. The pressure regulating structure can be an automatic pressure regulating mechanism formed by a motor and a ball screw. The motor drives the ball screw to rotate, causing the pressure block 32 to press down, thereby adjusting the clamping force of each pressure block 32.

[0040] like Figures 3 to 5As shown, in one embodiment, the crimping portion 512 is disposed on both sides of the width of the welding portion 511. The pressure block 32 is provided with a through groove 322 and pressure posts 323 located on both sides of the through groove 322. The through groove 322 is disposed corresponding to the position of the welding portion 511. At the same time, the slot 311 of the pressure plate 31 communicates with the through groove 322 to expose the welding portion 511 to the outside for laser welding. The pressure posts 323 are located on both sides of the through groove 322 and press against the surface of the crimping portion 512 respectively. In this embodiment, for a terminal group with two terminals 51, there are two through grooves 322 and three pressure posts 323, located on both sides and in the middle of the through groove 322 respectively. The width of the middle pressure post 323 is greater than that of the two side pressure posts 323. The middle pressure post 323 simultaneously crimps the adjacent crimping portions 512 of two terminals 51 in a group of terminals 51. For a terminal group with three terminals 51, if there are three through slots 322, then there are four pressure posts 323, located on both sides of the through slots 322 and between two adjacent through slots 322. The middle pressure post 323 presses against the crimping portions 512 of adjacent terminals 51. The recesses 321 are symmetrically arranged on the front and rear sides of the through slots 322. The elastic force of the springs 33 in the recesses 321 can be evenly applied to the pressure blocks 32, and then to the crimping portions 512.

[0041] like Figure 1 , Figure 7 and Figure 8 As shown, in use, the pressure block 32 is installed in the opening 21, the spring 33 is placed in the recess 321, and the pressure plate 31 is locked to the cover plate 2 by the second bolt 7. At this time, the pressure plate 31 applies downward pressure to the spring 33, and the pressure is transmitted to the pressure block 32, and then to the crimping part 512, thereby pressing the welding part 511 to the contact part 41, ensuring the consistent fit of the welding part 511 of the terminal 51. The feeding operation of this invention is simple. The liner 4 is placed in the groove 11 of the base 1, then the frame 5 is placed in accordance with the anti-fooling post 13, the cover plate 2 is covered, and then the pressing mechanism 3 is installed to complete the assembly and pressing operation, which is suitable for mass production.

[0042] The present invention also provides a method for adjusting the clamping force based on the above-mentioned terminal laser welding clamping device, comprising the following steps.

[0043] The contact resistance between terminal 51 and contact portion 41 of liner 4 is obtained. In this embodiment, the four-terminal measurement method (Kelvin connection) is used to measure the contact resistance between solder portion 511 and contact portion 41 using a probe.

[0044] Determine whether the contact resistance has reached the set value. If not, adjust the pressure of the pressure block 32 to press the welding part 511 against the contact part 41 until the contact resistance between the terminal 51 and the contact part 41 reaches the preset value. If yes, then operate normally.

[0045] In one embodiment, the pressure block 32 has a recessed hole 321, and a spring 33 is provided inside the recessed hole 321. When the contact resistance is less than a set value, the elastic force of the spring 33 is adjusted so that the contact resistance reaches the set value. It should be noted that the elastic force of the spring 33 can be adjusted by replacing the spring 33 or by adjusting the stiffness or length of the spring 33.

[0046] In another embodiment, the clamping force of the pressure block 32 can also be adjusted by a pressure adjustment mechanism connected to the pressure block 32 so that the clamping force between the welding part 511 and the contact part 41 reaches a preset value.

[0047] This invention monitors whether the terminal 51 and the liner 4 are in contact by measuring the contact resistance between the terminal 51 and the liner 4, and judges whether the clamping force meets the requirements based on the value of the contact resistance, so that the clamping force of each terminal 51 can reach the preset value, thereby ensuring the stability of the penetration depth in laser welding, avoiding the occurrence of blasting or incomplete welding, and thus improving the quality of laser welding.

[0048] Although the invention has been described with reference to preferred embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the invention. In particular, the technical features mentioned in the various embodiments can be combined in any manner as long as there is no structural conflict. The invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A terminal laser welding clamping device, characterized in that, include: The base has a groove for accommodating the liner, and the top surface of the liner has a contact portion; A cover plate is disposed above the base, and a frame is fixed between the cover plate and the base. The frame is provided with a terminal, and the terminal is provided with a welding part. The welding part is located on the contact part, and a pressing part extends outward from the side edge of the welding part. The cover plate is provided with an opening. A clamping mechanism is movably disposed within the opening. The clamping mechanism is provided with a pressure block. When the clamping mechanism is tightened, the pressure block presses against the surface of the crimping part to press the welded part into contact with the contact part.

2. The terminal laser welding clamping device according to claim 1, characterized in that, The clamping mechanism includes: Pressure plate, fixed to the cover plate; The pressure block is disposed between the pressure plate and the terminal, and the pressure block has a recessed hole; and A spring is disposed in the recessed hole. The top of the spring is connected to the pressure plate, and the bottom of the spring is connected to the bottom surface of the recessed hole. The spring force presses the pressure block against the pressing part to press the welded part to the contact part.

3. The terminal laser welding clamping device according to claim 2, characterized in that, The frame is provided with multiple sets of terminals, and each set of terminals is provided with an independent pressure block. By adjusting the elastic force of the spring, force can be applied evenly to terminals of different heights.

4. The terminal laser welding clamping device according to claim 1, characterized in that, The pressure block is connected to the pressure regulating mechanism, which dynamically adjusts the pressure to make the clamping force between the welded part and the contact part reach a preset value.

5. The terminal laser welding clamping device according to claim 1, characterized in that, The crimping portion is disposed on both sides of the welding portion. The pressing block is provided with a through groove and pressing columns located on both sides of the through groove. The pressing columns press against the surface of the crimping portion. The through groove is correspondingly disposed to the welding portion. The pressing plate is provided with a slot, which communicates with the through groove to expose the welding portion to the outside for laser welding.

6. The terminal laser welding clamping device according to claim 1, characterized in that, The top surface of the crimping part is flush with the top surface of the welding part, and the bottom surface of the crimping part is higher than the bottom surface of the welding part, so that there is a gap between the crimping part and the liner.

7. The terminal laser welding clamping device according to claim 1, characterized in that, The bottom surface of the cover plate is provided with a stop block, which stops between the terminal and the chip in the middle of the backing plate to prevent soldering spatter from splashing onto the chip.

8. The terminal laser welding clamping device according to claim 1, characterized in that, The base is provided with positioning posts and anti-fool posts. The positioning posts are used to cooperate with the cover plate for positioning, and the anti-fool posts are used to cooperate with the frame for positioning.

9. A method for adjusting the clamping force of the terminal laser welding clamping device according to claim 1, characterized in that, include: Obtain the contact resistance between the terminal and the contact portion of the liner; Determine whether the contact resistance has reached the set value. If not, adjust the pressure of the pressure block to press the welding part against the contact part until the contact resistance between the terminal and the contact part reaches the preset value.

10. The clamping force adjustment method according to claim 9, characterized in that, The pressure block has a recessed hole, and a spring is installed in the recessed hole. When the contact resistance is less than a set value, the elastic force of the spring is adjusted so that the contact resistance reaches the set value.

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