Aluminum substrate and electrolytic capacitor welding assembly method

Abstract

This invention discloses a method for welding and assembling an aluminum substrate and electrolytic capacitors. The steps are as follows: First, place several capacitors in the receiving holes of a heat sink base plate; then, install a welding bracket on the front side of the aluminum substrate; then, fix the heat sink base plate to the aluminum substrate; then, solder the capacitor leads to the welding holes of the welding bracket; finally, cut off the bracket's support plate. This invention mounts the electrolytic capacitors on the back of the aluminum substrate, saving space and reducing the circuit board size by about 30% compared to traditional designs. When applied to motor controllers, it can greatly improve power density. The electrolytic capacitors can be placed closer to the MOSFET pins, improving their filtering effect and reliability. The welding bracket can be automatically welded in large batches using a pick-and-place machine, reducing the difficulty of reverse welding of electrolytic capacitors, replacing manual shaping in the welding of electrolytic capacitors to the aluminum substrate, increasing welding speed, simplifying the process, reducing processing costs, and greatly improving welding quality.

Description

Technical Field

[0001] This invention relates to the field of electronic technology, and more specifically to a method for welding and assembling an aluminum substrate and an electrolytic capacitor. Background Technology

[0002] Currently, most mass-produced circuit boards are manufactured using a pick-and-place machine. Electronic components are dispensed with adhesive and then attached to designated solder contacts on the circuit board. The solder paste is then heated to its melting point and soldered to the component leads. Afterward, cooling allows the solder paste to solidify, completing the soldering process. However, not all electronic components can be soldered using a pick-and-place machine. High-quality electrolytic capacitors used in the industry typically use through-hole packages, requiring manual soldering. This process suffers from high processing costs, low production efficiency, the risk of reverse polarity connection, and low product yield.

[0003] Aluminum substrates are the most common circuit board substrates, offering advantages such as good heat dissipation. Other components on aluminum substrates can be easily converted to surface mount packages, but through-hole packages present obstacles in their application. Therefore, the feasibility of soldering electrolytic capacitors onto aluminum substrates and the reliability of soldering quality are significant challenges. Summary of the Invention

[0004] To simplify the welding process between aluminum substrate and electrolytic capacitor and reduce processing costs, this invention provides a welding and assembly method for aluminum substrate and electrolytic capacitor.

[0005] The technical solution adopted in this invention is as follows: A method for welding and assembling an aluminum substrate and an electrolytic capacitor, comprising the following steps:

[0006] Step 1: Place several electrolytic capacitors into the receiving holes of the heat sink base plate. The receiving holes correspond one-to-one with the capacitors, and the receiving holes are consistent with the installation positions of the capacitors on the aluminum substrate.

[0007] Step 2: Weld a bracket at the mounting position of each capacitor on the front side of the aluminum substrate. The bracket includes a support plate and two legs at both ends. The support plate is provided with two welding holes, and the two legs are welded to the welding positions on the aluminum substrate.

[0008] Step 3: Assemble the heat dissipation base plate on the back of the aluminum substrate and fix it in place. The capacitor leads pass through the through holes of the aluminum substrate and the welding holes of the bracket in sequence.

[0009] Step 4: Solder the two leads of all capacitors to the two solder holes of the corresponding bracket one by one;

[0010] Step 5: Cut off the tabs of all the brackets to isolate the two leads of the capacitor.

[0011] Preferably, in step one, the heat dissipation base plate is a high thermal conductivity metal plate.

[0012] Preferably, in step one, the receiving hole and the capacitor are in a clearance fit, and the capacitor is encapsulated in the receiving hole with thermally conductive adhesive.

[0013] Preferably, in step two, the welding holes are arranged at both ends of the support piece, and the middle part of the support piece is the cut-off part.

[0014] Preferably, in step two, the lower end of the support leg is bent outward to have a horizontal welding end, which is used for welding to the welding position on the aluminum substrate.

[0015] Preferably, in step two, the bracket is integrally pressed from copper sheet.

[0016] Preferably, in step three, before the heat sink base plate and the aluminum substrate are installed, insulating sleeves are fitted onto the leads of the capacitor.

[0017] The present invention has the following beneficial effects:

[0018] 1. By reverse-mounting and soldering the electrolytic capacitor to the aluminum substrate, space can be saved as much as possible, reducing the size of the circuit board by about 30%. When used as a motor controller, this greatly improves the power density of the controller, making it particularly suitable for use in confined spaces.

[0019] 2. The electrolytic capacitor is soldered closer to the MOSFET pin on the aluminum substrate, which greatly improves the filtering effect of the electrolytic capacitor and enhances its reliability;

[0020] 3. The electrolytic capacitor is mounted and fixed on the heat sink base plate. The heat sink plate has a certain degree of flatness and can maintain good contact with the external structure after installation. Even with a small circuit board size, it can still ensure good heat dissipation performance.

[0021] 4. The design of the welding bracket solves the process problem of reverse mounting and welding of electrolytic capacitors and aluminum substrates. The welding bracket can be automatically welded in large batches by a pick-and-place machine, replacing the manual shaping in the welding of electrolytic capacitors and aluminum substrates, simplifying the process, increasing the welding speed, reducing processing costs, and greatly improving the welding quality. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of step one in the method of an embodiment of the present invention.

[0023] Figure 2 This is a schematic diagram of step two in the method of an embodiment of the present invention.

[0024] Figure 3 This is a schematic diagram of step three in the method of an embodiment of the present invention.

[0025] Figure 4 This is a schematic diagram of step four in the method of an embodiment of the present invention.

[0026] Figure 5 This is a schematic diagram of step five in the method of an embodiment of the present invention.

[0027] Figure 6 This is a schematic diagram of the bracket in an embodiment of the present invention.

[0028] Bracket 1, support plate 101, support leg 102, welding hole 103, welding end 104, cut-off part 105; electrolytic capacitor 2, pin 201; aluminum substrate 3, welding position 301, through hole 302; insulating sleeve 4; heat dissipation base plate 5, receiving hole 501. Detailed Implementation

[0029] The present invention will be further described below with reference to the embodiments and accompanying drawings.

[0030] like Figures 1-5 The image shows a welding and assembly method for an aluminum substrate and electrolytic capacitor in the motor controller of a new type of electric bicycle. The specific steps are as follows:

[0031] Step 1: Place several electrolytic capacitors 2 into the receiving holes 501 of the heat dissipation base plate 5. The receiving holes 501 correspond one-to-one with the capacitors 2, and the receiving holes 501 are consistent with the installation positions of the electrolytic capacitors 2 on the circuit board 3.

[0032] The heat sink base plate 5 and the electrolytic capacitor 2 are fitted with a clearance, and a high thermal conductivity metal plate can be used. Before placing the electrolytic capacitor 2, an insulating material needs to be placed at the bottom of the receiving hole 501 of the heat sink base plate 5 to ensure good insulation between the electrolytic capacitor 2 and the heat sink base plate 5. Moreover, the electrolytic capacitor 2 is encapsulated in the receiving hole 501 with thermally conductive adhesive. This structure allows for more sufficient contact between the electrolytic capacitor 2 and the heat sink 5, which is beneficial for external heat conduction and heat dissipation.

[0033] Step 2: Weld bracket 1 at the mounting position of each capacitor 2 on the front side of aluminum substrate 3. The bracket 1 includes a support plate 101 and two legs 102 at both ends. The support plate 101 is provided with two welding holes 103, and the two legs 102 are welded to the welding position 301 on the circuit board 3.

[0034] The bracket 1 is integrally pressed from copper sheet. The lower end of the support leg 102 is bent outward to form a horizontal welding end 104 for welding to the welding position 301 on the aluminum substrate 3. This structure allows the welding bracket 1 to be directly welded onto the aluminum substrate 3 using a pick-and-place machine. Welding holes 103 are arranged at both ends of the bracket 101. The middle part of the bracket 101 is a cut-off portion 105. The width of the cut-off portion 105 is smaller than the width at both ends of the bracket 101. After the capacitor 2 is welded, the electrolytic capacitor 2 can be prevented from short-circuiting by shortening the cut-off portion 105. The cut-off portion 105 itself is relatively narrow, so cutting is also convenient.

[0035] Step 3: Assemble the heat dissipation base plate 5 on the back of the aluminum substrate 3 and fix it in place. The pins 201 of the electrolytic capacitor 2 pass through the through holes 302 of the circuit board 3 and the welding holes 103 of the bracket 1 in sequence.

[0036] Before the heat dissipation base plate 5 and the aluminum substrate 3 are installed, an insulating sleeve 4 is fitted onto the pins 201 of the electrolytic capacitor 2. The insulating sleeve 4 supports the pins 201, which can play a certain role in fixing them and can also prevent the pins 201 from directly contacting the through hole 302.

[0037] Step 4: Solder the two pins 201 of all capacitors 2 to the two solder holes 103 of the corresponding bracket 1 one by one.

[0038] Step 5: Cut off the tabs 101 of all brackets 1 to isolate the two pins 201 of capacitor 2.

[0039] The assembly and welding method of the motor controller and its aluminum substrate with the electrolytic capacitor in this embodiment has the following advantages:

[0040] (1) The electrolytic capacitor 2 and the aluminum substrate 3 are installed and welded in opposite directions to save space as much as possible. This can reduce the size of the motor controller by about 30%, thereby greatly improving the power density of the controller. With the same size as the traditional controller, the motor power can be increased from 3KW to 7KW. Therefore, it is particularly suitable for use in places with limited space, such as electric bicycle frames.

[0041] (2) The welding position of the electrolytic capacitor 2 on the aluminum substrate 3 can be closer to the pin of the MOS transistor, which greatly improves the filtering effect of the electrolytic capacitor and improves the reliability of the controller.

[0042] (3) The electrolytic capacitor 2 is installed and fixed on the heat dissipation base plate 5. The heat dissipation base plate 5 has a certain flatness. After it is installed with the frame of the electric bicycle and locked with bolts, it can maintain good contact. In this way, heat can be transferred to the outside through the entire frame. While the controller is small in size, it ensures good heat dissipation performance, which in turn promotes the controller to achieve higher power density.

[0043] (4) The design of the welding bracket 1 solves the process problem of reverse mounting welding of electrolytic capacitor 2 and aluminum substrate 3. The welding bracket 1 can be automatically welded in large batches by a chip mounter, replacing the manual shaping in the welding of electrolytic capacitor 2 and aluminum substrate 3, simplifying the process, increasing the welding speed, reducing the processing cost, and greatly improving the welding quality.

[0044] Obviously, the above embodiments of the present invention are merely illustrative examples to illustrate the invention and are not intended to limit the implementation of the invention. Other obvious variations or modifications derived from the essential spirit of the invention still fall within the protection scope of the invention.

Claims

1. A method for welding and assembling an aluminum substrate with an electrolytic capacitor, characterized in that, The steps are as follows: Step 1: Place several electrolytic capacitors (2) into the receiving holes (501) of the heat dissipation base plate (5). The receiving holes (501) correspond one-to-one with the capacitors (2), and the receiving holes (501) are consistent with the installation positions of the capacitors (2) on the aluminum substrate (3). Step 2: Weld brackets (1) at the mounting positions of each capacitor (2) on the front side of the aluminum substrate (3). The brackets (1) include a support plate (101) and legs (102) at both ends. The support plate (101) is provided with two welding holes (103). The two legs (102) are welded to the welding positions (301) on the aluminum substrate (3). Step 3: Assemble the heat dissipation base plate (5) on the back of the aluminum substrate (3) and fix it in place. The pins (201) of the capacitor (2) pass through the through hole (302) of the aluminum substrate (3) and the welding hole (103) of the bracket (1) in sequence. Step 4: Solder the two pins (201) of all capacitors (2) to the two solder holes (103) of the corresponding brackets (1); Step 5: Cut off the tabs (101) of all brackets (1) to isolate the two pins (201) of capacitor (2).

2. The method for welding and assembling an aluminum substrate and an electrolytic capacitor according to claim 1, characterized in that, In step one, the heat dissipation base plate (5) is a high thermal conductivity metal plate.

3. The method for welding and assembling an aluminum substrate and an electrolytic capacitor according to claim 1, characterized in that, In step one, the receiving hole (501) and the capacitor (2) are in clearance fit, and the capacitor (2) is encapsulated in the receiving hole (501) with thermally conductive adhesive.

4. The method for welding and assembling an aluminum substrate and an electrolytic capacitor according to claim 1, characterized in that, In step two, welding holes (103) are arranged at both ends of the support plate (101), and the middle part of the support plate (101) is the cut-off part (105).

5. The method for welding and assembling an aluminum substrate and an electrolytic capacitor according to claim 1, characterized in that, In step two, the lower end of the support leg (102) is bent outward to have a horizontal welding end (104) for welding to the welding position (301) on the aluminum substrate (3).

6. The method for welding and assembling an aluminum substrate and an electrolytic capacitor according to claim 1, characterized in that, In step two, the bracket (1) is integrally pressed from copper sheet.

7. The method for welding and assembling an aluminum substrate and an electrolytic capacitor according to claim 1, characterized in that, In step three, before the heat dissipation base plate (5) and the aluminum substrate (3) are installed, an insulating sleeve (4) is fitted on the pin (201) of the capacitor (2).

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