A controller capacitor welding structure and a welding method thereof

Abstract

This invention relates to the field of capacitor welding technology, and more particularly to a controller capacitor welding structure and welding method. The technical solution includes a PCB board, leads, capacitor copper busbars, and a cantilever beam base. The upper side of the middle of the lead has a V-shaped bend, and the lead's interior has a hollow channel and multiple through slots, with low-melting-point alloy particles placed within the through slots and hollow channels. Two capacitor copper busbars are respectively disposed on the upper and lower sides of the lead's outer wall, and each busbar has a tenon. A mortise is formed on the copper busbar inside the PCB board. A micro-gap exists between the cantilever beam base and the capacitor copper busbars, and a mass block is placed between the cantilever beam base and the PCB board. This invention absorbs thermal expansion stress through the V-shaped bend, captures vibration energy through the resonance of the cantilever beam base and the mass block, converting it into solder joint strengthening energy. The tenon and mortise structure achieves precise guiding and positioning of the capacitor copper busbars, and the built-in low-melting-point alloy particles enable self-repair of solder joint defects, significantly improving the long-term reliability of the controller capacitor solder joints.

Description

Technical Field

[0001] This invention relates to the field of capacitor welding technology, and in particular to a controller capacitor welding structure and welding method thereof. Background Technology

[0002] As the core control unit of electronic equipment, the controller integrates a large number of capacitors for filtering, energy storage, and voltage regulation. These capacitors are typically soldered to pads on the PCB board via pins, forming both electrical pathways and mechanical fixation. During controller operation, the capacitors must withstand thermal cycling from ambient temperature changes and mechanical stress from equipment vibrations, placing stringent requirements on the long-term reliability of the solder joints.

[0003] In existing technologies, controller capacitors are primarily soldered using wave soldering or reflow soldering processes, forming a metallurgical bond between the capacitor leads and PCB pads using solder. To improve the fatigue resistance of the solder joints, some improvements employ methods such as increasing the solder joint size, applying adhesive for reinforcement, or adding auxiliary clips to strengthen the connection. Regarding thermal stress management, some designs absorb thermal expansion differences by incorporating bending structures at the lead roots; for vibration protection, shock-absorbing brackets or elastic pads are typically used to isolate the controller from vibration sources.

[0004] However, in the above-mentioned technical solutions, after welding, the weld joints inevitably suffer cumulative damage from thermal cycling and vibration during long-term service. Microcracks gradually initiate and propagate, eventually leading to weld joint failure. Existing technologies lack the ability to actively repair existing damage. Once microcracks appear in the weld joints, they irreversibly fail, severely limiting the lifespan of the controller. Summary of the Invention

[0005] The purpose of this invention is to address the problems existing in the background art by proposing a controller capacitor welding structure and its welding method.

[0006] In a first aspect, this application provides a controller capacitor soldering structure, including a PCB board, and further comprising: A pin located in the middle of the PCB board has a V-shaped bend on the upper side of the middle part of the pin, and a capacitor body is installed on the top of the pin; The capacitor copper busbars are located on the upper and lower sides of the middle of the outer wall of the pins. The two capacitor copper busbars are equipped with tenon and mortise positioning parts on opposite sides of their outer walls. The tenon and mortise positioning parts are inserted into the PCB board. The outer sides of the two capacitor copper busbars are equipped with cantilever beam bases, and a micro gap is formed between the cantilever beam bases and the capacitor copper busbars. The edges of the two cantilever beam bases are curved, and their arc surfaces abut against the upper and lower surfaces of the PCB board. A mass block is set between the PCB board and the cantilever beam bases. The pin has a hollow channel in the middle and multiple through slots on the inside and outside of the pin, and the multiple through slots are connected to the hollow channel. The pin has multiple low-melting-point alloy particles inside, and the multiple low-melting-point alloy particles are all disposed inside the through slots.

[0007] Optionally, the cantilever beam base includes a first cantilever segment and a second cantilever segment. One end of the first cantilever segment is fixedly connected to the outer wall of the capacitor copper busbar, and the other end of the first cantilever segment is integrally connected to one end of the second cantilever segment. The other end of the second cantilever segment is curved and its arc surface abuts against the upper or lower surface of the PCB board.

[0008] Optionally, the mass block is fixedly disposed between the second cantilever segment and the PCB board, and the upper surface of the mass block is fixedly connected to the lower surface of the second cantilever segment, and a gap is provided between the lower surface of the mass block and the upper or lower surface of the PCB board.

[0009] Optionally, the V-shaped bend is located on the upper side of the middle of the pin, and the opening of the V-shaped bend faces the axial direction of the pin. The part of the pin located on the upper side of the V-shaped bend is fixedly connected to the electrode of the capacitor body, and the part of the pin located on the lower side of the V-shaped bend passes through the interior of the PCB board.

[0010] Optionally, the tenon and mortise positioning component includes a tenon and a mortise. The tenon is fixedly set on the opposite sidewalls of the two capacitor copper busbars and extends protruding into the PCB board. The mortise is opened on the copper busbar inside the PCB board. The tenon passes through the inside of the PCB board and is embedded in the mortise.

[0011] Optionally, an external thread is provided on the lower side of the outer wall of the pin, and an internal thread matching the external thread is provided on the inner wall of the capacitor copper busbar located on the lower side of the outer wall of the pin.

[0012] Secondly, the present invention provides a controller capacitor welding method, applied to the controller capacitor welding structure described in the first aspect, the method comprising the following steps: S1. Insert the leads of the capacitor body into the preset holes on the PCB board, so that the V-shaped bend is locked on the upper surface of the PCB board. S2. Tighten the two capacitor copper busbars to the upper and lower sides of the outer wall of the pins respectively, so that the tenons on the two capacitor copper busbars pass through the inside of the PCB board and are embedded in the corresponding mortise on the copper busbar inside the PCB board. S3. Fix one end of the cantilever beam base to the outer wall of the capacitor copper busbar, so that the curved part of the edge of the cantilever beam base abuts against the upper and lower surfaces of the PCB board respectively, and fix the mass block between the cantilever beam base and the PCB board. S4. Heat and solder the contact parts of the pins, capacitor copper busbars and PCB board, so that the low melting point alloy particles inside the through slot and hollow channel melt and flow out to fill the gap between the pins and the PCB board.

[0013] Optionally, in S1, after the pin is inserted into the PCB board, the lower side of the V-shaped bend contacts the upper surface of the PCB board, and the portion of the pin located on the lower side of the V-shaped bend penetrates the PCB board and extends out from the lower surface of the PCB board.

[0014] Optionally, in S2, after the two capacitor copper busbars are screwed and installed on the upper and lower sides of the outer wall of the pin, the inner side wall of the capacitor copper busbars fits against the outer side wall of the pin, and the tenons on the two capacitor copper busbars pass through the inside of the PCB board and are completely embedded in the corresponding mortise on the copper busbar inside the PCB board.

[0015] Optionally, in S4, the heating and welding temperature is higher than the melting point of the low-melting-point alloy particles and lower than the damage temperature of the pins, capacitor copper busbars and PCB board. After the molten low-melting-point alloy particles flow out through the channel, they fill and solidify along the gap between the outer wall of the pin and the PCB board.

[0016] In summary, this application includes at least one of the following beneficial technical effects: This invention provides a V-shaped bend on the upper side of the middle of the pin, which absorbs the thermal expansion difference caused by thermal cycling through its elastic deformation. This avoids the direct transfer of thermal stress to the welding interface and significantly reduces the risk of the solder joint cracking due to thermal fatigue.

[0017] Furthermore, by utilizing the resonant structure of the cantilever beam base and the mass block, the environmental vibration energy during the controller's operation is captured and converted into frictional heat and alternating stress, which act on the welding interface to achieve microscopic reflow of solder and grain refinement, thereby continuously strengthening the solder joint during service and effectively extending its fatigue life.

[0018] Finally, by setting hollow channels, through slots, and low-melting-point alloy particles inside the pins, the solder can be self-filled by capillary action. After microcracks appear in the solder joint, the residual alloy particles are melted again to achieve multiple in-situ self-repair, thus solving the technical problem of irreversible solder joint damage. Attached Figure Description

[0019] Figure 1 A schematic diagram of the overall structure of a controller capacitor welding structure according to the present invention is provided. Figure 2 A schematic diagram of the internal structure of a PCB board with a capacitor-bonded controller structure; Figure 3 A schematic diagram of the pin structure of a controller capacitor-bonded structure; Figure 4 for Figure 3 Schematic diagram of the structure at point A in the middle; Figure 5 This is a flowchart of a controller capacitor welding method.

[0020] Reference numerals: 1. PCB board; 2. Pin; 3. V-shaped bend; 4. Capacitor body; 5. Cantilever beam base; 6. Micro-gap; 7. Mass block; 8. Tenon and mortise positioning component; 9. Through slot; 10. Low melting point alloy particles; 11. Capacitor copper busbar; 12. External thread; 13. Hollow channel. Detailed Implementation

[0021] 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 some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] like Figures 1-4 As shown, the present invention proposes a controller capacitor welding structure, including a PCB board 1, pins 2 disposed in the middle of the PCB board 1, capacitor copper busbars 11 disposed on the upper and lower sides of the middle of the outer wall of the pins 2, a hollow channel 13 opened in the middle of the pins 2, and multiple through slots 9 opened inside and outside the pins 2; a V-shaped bend 3 is provided on the upper side of the middle of the pins 2, and a capacitor body 4 is installed on the top of the pins 2; tenon and tenon positioning parts 8 are installed on opposite sides of the outer walls of the two capacitor copper busbars 11, the tenon and tenon positioning parts 8 are inserted into the PCB board 1, and cantilever beam bases 5 are installed on the outer sides of the outer walls of the two capacitor copper busbars 11, and a micro gap 6 is formed between the cantilever beam bases 5 and the capacitor copper busbars 11; the edges of the two cantilever beam bases 5 are designed to be curved, and their arc surfaces abut against the upper and lower surfaces of the PCB board 1, and a mass block 7 is provided between the PCB board 1 and the cantilever beam bases 5; multiple through slots 9 are connected to the hollow channel 13, and multiple low melting point alloy particles 10 are provided inside the pins 2, and multiple low melting point alloy particles 10 are all disposed inside the through slots 9; The cantilever beam base 5 includes a first cantilever segment and a second cantilever segment. One end of the first cantilever segment is fixedly connected to the outer wall of the capacitor copper busbar 11, and the other end of the first cantilever segment is integrally connected to one end of the second cantilever segment. The other end of the second cantilever segment is curved, and its arc surface abuts against the upper or lower surface of the PCB board 1. A mass block 7 is fixedly disposed between the second cantilever segment and the PCB board 1, and the upper surface of the mass block 7 is fixedly connected to the lower surface of the second cantilever segment. A gap is provided between the lower surface of the mass block 7 and the upper or lower surface of the PCB board 1. The V-shaped bend 3 is located on the upper side of the middle of the pin 2, and the opening of the V-shaped bend 3 faces... Along the axial direction of pin 2, the portion of pin 2 located on the upper side of the V-shaped bend 3 is fixedly connected to the electrode of capacitor body 4, and the portion of pin 2 located on the lower side of the V-shaped bend 3 passes through the interior of PCB board 1; the tenon and mortise positioning component 8 includes a tenon and a mortise, the tenon is fixedly set on the opposite sidewalls of the two capacitor copper busbars 11 and extends protruding into the interior of PCB board 1, the mortise is opened on the copper busbar inside PCB board 1, and the tenon passes through the interior of PCB board 1 and is embedded in the mortise; an external thread 12 is opened on the lower middle side of the outer wall of pin 2, and an internal thread matching the external thread 12 is opened on the inner wall of the capacitor copper busbar 11 located on the lower middle side of the outer wall of pin 2; In this embodiment, the low-melting-point alloy particles 10 are preferably Sn. - The 58Bi eutectic alloy particles contain 58% bismuth and 42% tin by weight, with a eutectic melting point of 138℃±2℃. The particles are spherical or near-spherical in shape, with a particle size controlled between 10μm and 50μm. They are filled into the through-slot 9 and the hollow channel 13 via vacuum filling. The capacitor welding structure is described in detail below: In this embodiment, after the capacitor body 4 is mounted on the PCB board 1 via the pin 2, the V-shaped bend 3 on the upper side of the pin 2 is located between the capacitor body 4 and the PCB board 1. The opening of the V-shaped bend 3 faces the axial direction of the pin 2, forming a bent structure with elastic buffering capability. During normal operation of the controller, changes in ambient temperature will cause a difference in thermal expansion between the PCB board 1 and the capacitor body 4. The PCB board 1 typically has a higher coefficient of thermal expansion, while the capacitor body 4 has a relatively lower coefficient of thermal expansion. When the temperature rises, the expansion of the PCB board 1 is greater than that of the capacitor body 4, resulting in a relative displacement tendency between the two. At this time, the V-shaped bend 3 undergoes elastic deformation, absorbing this displacement difference through a small change in its opening angle, thereby avoiding the direct transfer of thermal stress to the soldering interface. When the temperature drops, the V-shaped bend 3 returns to its original shape, always maintaining reliable contact between the pin 2 and the PCB board 1.

[0023] During controller operation, external vibrations are transmitted to the PCB board 1 and capacitor body 4 through the controller housing. At this time, a micro-gap 6 is reserved between the cantilever beam base 5 and the capacitor copper busbar 11. The existence of this micro-gap 6 means that the cantilever beam base 5 is not completely rigidly fixed to the capacitor copper busbar 11, but has a certain degree of freedom of deformation. When the vibration frequency approaches the natural frequency of the cantilever beam base 5, the cantilever beam base 5 resonates, and the amplitude at its free end is significantly amplified. The mass block 7 fixed to the inside of the free end of the cantilever beam base 5 further enhances this resonance effect; the larger the mass block 7 and the longer the length of the cantilever beam base 5, the higher the resonance amplification factor.

[0024] During resonance, a regular, micron-level relative motion occurs between the curved edge of the cantilever beam base 5 and the upper and lower surfaces of the PCB board 1. The reciprocating motion of the cantilever beam base 5 generates minute frictional heat at its contact interface with the capacitor busbar 11. This heat is conducted through the capacitor busbar 11 to the soldering interface, causing a microscopic reflow effect in the solder, thereby eliminating microcracks and stress concentration points within the solder joint. Furthermore, the periodic vibration of the cantilever beam base 5 applies alternating compressive and tensile stresses to the soldering interface. This alternating stress effect is similar to a micro-forging effect, refining the solder grains, increasing the density of the solder joint structure, and thus enhancing the fatigue resistance of the solder joint.

[0025] The pin 2 has a hollow channel 13 and multiple through slots 9 inside. The hollow channel 13 extends axially along the pin 2, and the multiple through slots 9 connect the hollow channel 13 to the outer wall of the pin 2 radially. The through slots 9 and the hollow channel 13 are pre-filled with multiple low-melting-point alloy particles 10.

[0026] During the heating and welding process, when the welding temperature reaches the preset value, the low-melting-point alloy particles 10 melt into liquid solder. In this process, the heating and welding temperature is set to 150℃~200℃, which is higher than that of Sn. - The eutectic melting point of 58Bi is 138℃, which is lower than the damage temperature of pin 2 (copper), capacitor busbar 11 (copper), and PCB board 1 (FR4 substrate has a long-term temperature resistance of about 260℃, and the internal temperature resistance of electrolytic capacitors generally does not exceed 150℃, but thermal damage can be avoided by controlling the soldering time). Because the hollow channel 13 and the through-slot 9 are interconnected to form a capillary network, the molten solder is automatically drawn into the gap between the outer wall of pin 2 and PCB board 1 under capillary action. This self-flowing filling mechanism ensures that every corner of the soldering interface is fully covered by solder, effectively eliminating porosity and void defects common in traditional soldering processes.

[0027] More importantly, even after welding is completed, if the controller develops new microcracks due to thermal cycling or vibration during long-term use, when the controller is exposed to a high-temperature environment again, the low-melting-point alloy particles 10 remaining in the hollow channel 13 will melt again and penetrate into the newly generated cracks through the through groove 9, thus achieving multiple self-repair of the weld.

[0028] Two capacitor copper busbars 11 are respectively disposed on the upper and lower sides of the outer wall of the pin 2, and respectively attached to the upper and lower surfaces of the PCB board 1. Each capacitor copper busbar 11 has a tenon protruding into the PCB board 1 fixedly disposed on the opposite side wall, and a mortise matching the tenon is provided on the copper busbar inside the PCB board 1.

[0029] During the process of screwing the capacitor busbar 11 onto the pin 2, the tenon first enters the channel inside the PCB board 1. As the screwing depth increases, the tenon gradually approaches the mortise. When the tenon contacts the entrance of the mortise, the tapered or rounded guide surface of the tenon engages with the chamfered entrance of the mortise, automatically converting the rotational motion of the capacitor busbar 11 into axial guide displacement, guiding the capacitor busbar 11 to precisely align with the preset position. After the tenon is fully embedded in the mortise, the capacitor busbar 11 is locked in the radial direction, ensuring that the electrical contact area between the capacitor busbar 11 and the copper busbar inside the PCB board 1 is maximized and the contact resistance is minimized.

[0030] like Figures 1-5 As shown, the present invention also provides a method for soldering controller capacitors, the method comprising the following steps: S1. Insert the pins 2 of the capacitor body 4 into the preset holes of the PCB board 1, so that the V-shaped bend 3 is locked on the upper surface of the PCB board 1. S2. Tighten the two capacitor copper busbars 11 to the upper and lower sides of the outer wall of the pin 2 respectively, so that the tenons on the two capacitor copper busbars 11 pass through the inside of the PCB board 1 and are embedded in the corresponding mortise on the copper busbar inside the PCB board 1. S3. Fix one end of the cantilever beam base 5 to the outer wall of the capacitor copper busbar 11, so that the curved part of the edge of the cantilever beam base 5 abuts against the upper and lower surfaces of the PCB board 1 respectively, and fix the mass block 7 between the cantilever beam base 5 and the PCB board 1. S4. Heat and weld the contact parts of pin 2, capacitor copper busbar 11 and PCB board 1, so that the low melting point alloy particles 10 inside the through groove 9 and the hollow channel 13 melt and flow out to fill the gap between pin 2 and PCB board 1. In step S1, after pin 2 is inserted into PCB board 1, the lower side of the V-shaped bend 3 contacts the upper surface of PCB board 1, and the part of pin 2 located on the lower side of the V-shaped bend 3 penetrates PCB board 1 and extends from the lower surface of PCB board 1. In step S2, after two capacitor copper busbars 11 are screwed and installed on the upper and lower sides of the outer wall of pin 2, the inner side wall of capacitor copper busbar 11 fits against the outer side wall of pin 2, and the tenons on the two capacitor copper busbars 11 pass through the interior of PCB board 1 and are completely embedded in the corresponding mortise on the copper busbar inside PCB board 1. In step S4, the heating and welding temperature is higher than the melting point of low melting point alloy particles 10 and lower than the damage temperature of pin 2, capacitor copper busbar 11 and PCB board 1. After the molten low melting point alloy particles 10 flow out through the through groove 9, they fill and solidify along the gap between the outer side wall of pin 2 and PCB board 1.

[0031] Specifically, in step S1, the operator or automated equipment inserts the lead 2 of the capacitor body 4 into the preset hole in the PCB board 1. During this process, the V-shaped bend 3 plays a crucial role. When the lead 2 is inserted, the lower side of the V-shaped bend 3 contacts the upper surface of the PCB board 1, generating slight elastic compression. This elastic compression produces an upward rebound force, pulling the lead 2 upward and eliminating the axial gap between the lead 2 and the hole wall of the PCB board 1. Simultaneously, the portion of the lead 2 located below the V-shaped bend 3 penetrates the PCB board 1 and extends from the lower surface of the PCB board 1, providing sufficient soldering area for subsequent soldering.

[0032] This pre-fixing mechanism prevents the capacitor body 4 from sliding down due to gravity or vibration during subsequent operations, eliminating the need for additional clamps or pressure blocks and simplifying the production process.

[0033] In step S2, the capacitor copper busbar 11 is attached to the upper and lower sides of the outer wall of the pin 2 respectively: The internal thread on the inner wall of the bottom capacitor copper busbar 11 engages with the external thread 12 on the outer wall of the pin 2, converting the circular motion of the screwing into a linear motion of the capacitor copper busbar 11 along the axial direction of the pin 2. This threaded guidance makes the axial feed of the capacitor copper busbar 11 precisely controllable, avoiding tilting or jamming of the capacitor copper busbar 11 due to uneven force.

[0034] Furthermore, during the axial feeding of the capacitor copper busbar 11, the tenon fixed to the opposite sidewall of the capacitor copper busbar 11 first enters the channel inside the PCB board 1. As the feeding depth increases, the front end of the tenon contacts the mortise entrance on the copper busbar inside the PCB board 1. The mortise entrance is usually provided with a chamfer or rounded corner, which cooperates with the front guide surface of the tenon to automatically correct the slight offset of the capacitor copper busbar 11 in the radial direction. Even if there is a slight eccentricity in the capacitor copper busbar 11 at the beginning of the screwing, the eccentricity will be automatically corrected as the tenon gradually enters the mortise, so that the inner sidewall of the capacitor copper busbar 11 is completely fitted with the outer sidewall of the pin 2, and the tenon is completely embedded in the mortise.

[0035] It achieves adaptive calibration of coarse positioning followed by fine positioning during the installation process of capacitor copper busbar 11, which significantly reduces the requirements for assembly accuracy.

[0036] In step S3, one end of the cantilever beam base 5 is fixedly connected to the outer wall of the capacitor copper busbar 11. During this fixing process, the curved portion of the edge of the cantilever beam base 5 is pressed against the upper and lower surfaces of the PCB board 1, respectively, forming a certain preload. The preload keeps the curved edge of the cantilever beam base 5 in close contact with the surface of the PCB board 1, ensuring that no unexpected relative movement occurs between the two due to gaps.

[0037] Meanwhile, mass block 7 is fixedly positioned between cantilever beam base 5 and PCB board 1. The upper surface of mass block 7 is fixedly connected to the lower surface of cantilever beam base 5, while a preset gap is maintained between the lower surface of mass block 7 and the upper or lower surface of PCB board 1. If the gap is too small, mass block 7 will impact PCB board 1 during vibration, generating noise or even causing damage; if the gap is too large, it will reduce the vibration energy capture efficiency. By precisely controlling this gap, it is ensured that mass block 7 will not contact PCB board 1 within the normal vibration amplitude, while providing a limiting protection function under extreme impact conditions.

[0038] In step S4, the contact points of pin 2, capacitor copper busbar 11, and PCB board 1 are heated and soldered. The heating temperature is precisely controlled between 150°C and 200°C. This temperature range is higher than that of the low-melting-point alloy particles 10 (Sn). -The eutectic melting point of 58Bi is 138℃, ensuring sufficient melting of the particles; it is also lower than the oxidation intensification temperature (>250℃) of pin 2 and capacitor copper busbar 11, and lower than the glass transition temperature (approximately 260℃) of the PCB substrate. Furthermore, by controlling the soldering time (e.g., 3-5 seconds), heat damage to the internal dielectric of the capacitor body 4 is avoided. When the heating temperature reaches the preset value, the low-melting-point alloy particles 10 located inside the through-slot 9 and the hollow channel 13 begin to melt. Since the hollow channel 13 and the through-slot 9 form a connected capillary network, the molten liquid solder is automatically drawn from inside pin 2 to the gap between the outer wall of pin 2 and the PCB 1 under capillary action. The self-filling process does not require external pressure, and the filling speed is inversely proportional to the gap size. The smaller the gap, the greater the capillary force, and the more fully the solder is filled, thus automatically prioritizing the filling of the most difficult-to-solder micro-gap.

[0039] Furthermore, the molten low-melting-point alloy particles 10 wet the outer wall of pin 2, the hole wall of PCB board 1, and the contact surface of capacitor copper busbar 11. Since the surfaces of pin 2, capacitor copper busbar 11, and the hole wall of PCB board 1 are typically coated with a solderable plating, the liquid solder spreads on the surface and undergoes atomic-level interdiffusion, forming an intermetallic compound layer. Metallurgical bonding is the essence of welded connections, determining the electrical properties and mechanical strength of the solder joint.

[0040] During the solder filling process, air and flux volatiles that were originally present in the gaps are expelled by the molten solder. Because the capillary network formed by the through-slot 9 and the hollow channel 13 provides multiple venting channels, air bubbles are less likely to be trapped inside the solder joint, thus effectively reducing the void ratio. When heating stops, the solder cools and solidifies, forming a dense and continuous welded joint.

[0041] The heating and soldering temperature is precisely controlled to be higher than the melting point of the low-melting-point alloy particles 10 but lower than the damage temperature of pin 2, capacitor copper busbar 11, and PCB board 1. The temperature window setting ensures that the solder can melt fully while avoiding thermal damage to the internal dielectric of capacitor body 4, thermal decomposition of PCB board substrate, and excessive consumption of the plating on the surface of pin 2.

[0042] After soldering, the gap between the outer wall of pin 2 and PCB board 1 is completely filled and solidified by low-melting-point alloy particles 10. Even during long-term use, if micro-cracks appear at the solder joint due to thermal cycling or mechanical impact, when the controller is subjected to a high-temperature environment again, the small amount of low-melting-point alloy particles 10 remaining in the hollow channel 13 will melt again and seep into the newly generated cracks through the through groove 9, thus achieving in-situ repair of the solder joint.

[0043] The above specific embodiments are merely several optional embodiments of the present invention. Based on the technical solutions of the present invention and the relevant teachings of the above embodiments, those skilled in the art can make various alternative improvements and combinations to the above specific embodiments.

Claims

1. A controller capacitor soldering structure, comprising a PCB board (1), characterized in that, Also includes: A pin (2) is set in the middle of the PCB board (1), a V-shaped bend (3) is provided on the upper side of the middle of the pin (2), and a capacitor body (4) is installed on the top of the pin (2). The capacitor copper busbars (11) are set on the upper and lower sides of the middle of the outer wall of the pin (2). The two capacitor copper busbars (11) are equipped with tenon and tenon positioning parts (8) on opposite sides of the outer wall. The tenon and tenon positioning parts (8) are inserted into the PCB board (1). The two capacitor copper busbars (11) are equipped with cantilever beam bases (5) on the outer side of the outer wall. A micro gap (6) is formed between the cantilever beam bases (5) and the capacitor copper busbars (11). The edges of the two cantilever beam bases (5) are curved. Their arc surfaces abut against the upper and lower surfaces of the PCB board (1). A mass block (7) is set between the PCB board (1) and the cantilever beam bases (5). A hollow channel (13) is formed in the middle of the pin (2) and a plurality of through slots (9) are formed inside and outside the pin (2), and the plurality of through slots (9) are connected to the hollow channel (13). A plurality of low melting point alloy particles (10) are provided inside the pin (2), and the plurality of low melting point alloy particles (10) are all provided inside the through slots (9).

2. The controller capacitor welding structure according to claim 1, characterized in that, The cantilever beam base (5) includes a first cantilever section and a second cantilever section. One end of the first cantilever section is fixedly connected to the outer wall of the capacitor copper busbar (11). The other end of the first cantilever section is integrally connected to one end of the second cantilever section. The other end of the second cantilever section is curved and its arc surface abuts against the upper or lower surface of the PCB board (1).

3. The controller capacitor welding structure according to claim 1, characterized in that, The mass block (7) is fixedly disposed between the second cantilever section and the PCB board (1), and the upper surface of the mass block (7) is fixedly connected to the lower surface of the second cantilever section. A gap is provided between the lower surface of the mass block (7) and the upper or lower surface of the PCB board (1).

4. The controller capacitor welding structure according to claim 1, characterized in that, The V-shaped bend (3) is located on the upper side of the middle part of the pin (2), and the opening of the V-shaped bend (3) faces the axis of the pin (2). The part of the pin (2) located on the upper side of the V-shaped bend (3) is fixedly connected to the electrode of the capacitor body (4), and the part of the pin (2) located on the lower side of the V-shaped bend (3) passes through the interior of the PCB board (1).

5. The controller capacitor welding structure according to claim 1, characterized in that, The tenon and mortise positioning component (8) includes a tenon and a mortise. The tenon is fixedly set on the opposite sidewalls of the two capacitor copper busbars (11) and extends protruding into the PCB board (1). The mortise is opened on the copper busbar inside the PCB board (1). The tenon passes through the inside of the PCB board (1) and is embedded in the mortise.

6. The controller capacitor welding structure according to claim 1, characterized in that, The lower side of the outer wall of the pin (2) is provided with an external thread (12), and the inner wall of the capacitor copper busbar (11) located on the lower side of the outer wall of the pin (2) is provided with an internal thread that matches the external thread (12).

7. A controller capacitor welding method, applied to a controller capacitor welding structure according to any one of claims 1-6, characterized in that, The method includes the following steps: S1. Insert the pins (2) of the capacitor body (4) into the preset holes of the PCB board (1) so that the V-shaped bend (3) is locked on the upper surface of the PCB board (1). S2. Tighten the two capacitor copper busbars (11) to the upper and lower sides of the outer wall of the pin (2) respectively, so that the tenons on the two capacitor copper busbars (11) pass through the inside of the PCB board (1) and are embedded in the corresponding mortise on the copper busbar inside the PCB board (1). S3. Fix one end of the cantilever beam base (5) to the outer wall of the capacitor copper busbar (11), so that the curved part of the edge of the cantilever beam base (5) abuts against the upper and lower surfaces of the PCB board (1), and fix the mass block (7) between the cantilever beam base (5) and the PCB board (1). S4. Heat and weld the contact parts of the pin (2), capacitor copper busbar (11) and PCB board (1) so that the low melting point alloy particles (10) inside the through groove (9) and the hollow channel (13) melt and flow out to fill the gap between the pin (2) and PCB board (1).

8. A controller capacitor welding method according to claim 7, characterized in that, In S1, after the pin (2) is inserted into the PCB board (1), the lower side of the V-shaped bend (3) contacts the upper surface of the PCB board (1), and the part of the pin (2) located on the lower side of the V-shaped bend (3) passes through the PCB board (1) and extends out from the lower surface of the PCB board (1).

9. A controller capacitor welding method according to claim 7, characterized in that, In S2, after the two capacitor copper busbars (11) are screwed and installed on the upper and lower sides of the outer wall of the pin (2), the inner side wall of the capacitor copper busbar (11) is in contact with the outer side wall of the pin (2), and the tenons on the two capacitor copper busbars (11) pass through the inside of the PCB board (1) and are completely embedded in the corresponding grooves on the copper busbar inside the PCB board (1).

10. A controller capacitor welding method according to claim 7, characterized in that, In S4, the heating and welding temperature is higher than the melting point of the low melting point alloy particles (10) and lower than the damage temperature of the pin (2), the capacitor copper busbar (11) and the PCB board (1). After the molten low melting point alloy particles (10) flow out through the channel (9), they fill and solidify along the gap between the outer wall of the pin (2) and the PCB board (1).

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