A fully-sealed chip mount tantalum capacitor

Abstract

This utility model discloses a fully sealed surface-mount tantalum capacitor, comprising a shell, a core, and a cover plate. One side of the shell is connected to the cover plate. A positive and negative lead are provided on the outer wall of the shell. The core is disposed inside the shell and connected to the inner wall of the shell through a conductive layer. An anode wire is provided on the core, with one end connected to a lead wire. The lead wire passes through the cover plate and connects to the positive lead. This capacitor employs a metal shell encapsulation structure, improving the capacitor's hermeticity and enabling it to maintain good performance even in harsh environments such as high temperature and high humidity. The connection point between the tantalum wire lead wire and the anode wire is flattened to increase the contact area and enhance welding strength. Furthermore, the welding point is located inside the metal shell, increasing the reliability of the connection. The metal shell is covered with a first insulating layer, followed by a third and fourth insulating layers, providing double-layer insulation protection and improving reliability.

Description

Technical Field

[0001] This utility model belongs to the field of electronic component technology, and in particular relates to a fully sealed chip-mount tantalum capacitor. Background Technology

[0002] Traditional tantalum chip capacitors are moisture-sensitive devices due to the influence of their packaging materials. During use, moisture in high-temperature and high-humidity environments can cause their electrical performance parameters to drift or fail. While axial or longitudinal cylindrical metal-cased products can be used in harsh environments such as high temperature and high humidity, their structural characteristics make installation inconvenient. Therefore, there is a need for miniaturized tantalum chip capacitors that can improve the stability and reliability of their electrical performance parameters in harsh environments. Summary of the Invention

[0003] To solve the above-mentioned technical problems, this utility model provides a fully sealed surface-mount tantalum capacitor.

[0004] This utility model is achieved through the following technical solution.

[0005] This utility model provides a fully sealed surface-mount tantalum capacitor, including a shell, a core, and a cover plate. One side of the shell is connected to the cover plate. A positive terminal and a negative terminal are provided on the outer wall of the shell. The core is disposed inside the shell and is connected to the inner wall of the shell through a conductive layer. An anode wire is provided on the core. One end of the anode wire is connected to a lead wire. The lead wire passes through the cover plate and is connected to the positive terminal.

[0006] Preferably, a stepped structure is formed on the inner side of the outer shell, and the stepped structure of the outer shell is connected to the cover plate. The stepped structure and the cover plate cooperate to form an axial limiting structure.

[0007] Preferably, the cover plate includes a second insulating layer and a fixing ring. The second insulating layer is connected to the outer shell through the fixing ring. The fixing ring is welded to the outer shell at a second welding point. An insulating sheet is provided on the anode wire, and one side of the insulating sheet is connected to the outer wall of the core.

[0008] Preferably, the core is covered with an oxide film layer, the oxide film layer is covered with a first outer layer, a second outer layer is disposed outside the first outer layer, and a third outer layer is disposed outside the second outer layer.

[0009] Preferably, the outer wall of the housing is provided with a positive electrode lead-out pad and a negative electrode lead-out pad, the positive electrode lead-out pad being connected to the positive electrode pin, and the negative electrode lead-out pad being connected to the negative electrode pin.

[0010] Preferably, the positive electrode lead pad is connected to the outer wall of the housing through a third insulating layer, the negative electrode lead pad is connected to the outer wall of the housing through a fourth insulating layer, and the negative electrode pin is soldered to the housing at a third solder point.

[0011] Preferably, the cover plate is provided with a first reinforcing post and a second reinforcing post, the positive electrode pin is welded to the first reinforcing post at a fourth solder point, and the positive electrode pin is welded to the second reinforcing post at a fifth solder point.

[0012] Preferably, a first insulating layer is provided on the outer side of the outer casing, the lead wire is soldered to the positive electrode pin at the first solder joint, and the anode wire is soldered to the lead wire at the seventh solder joint.

[0013] The beneficial effects of this utility model are as follows:

[0014] 1. The metal casing structure improves the gas-tightness of the capacitor, enabling it to maintain good performance even in harsh environments such as high temperature and high humidity.

[0015] 2. The connection point between the tantalum wire lead and the anode wire is flattened to increase the contact area between the two and enhance the welding strength; moreover, the welding point is located inside the metal shell, which increases the reliability of the connection.

[0016] 3. After the conductive layer is cured, its height is between one-half and three-quarters of the height of the tantalum core. In addition to its conductive properties, it also has the function of fixing and stabilizing the tantalum core.

[0017] 4. Metal reinforcing posts are led out from the cover plate to reinforce the stability of the leads and positive pins, ensuring that the tantalum capacitor can be used in different environments;

[0018] 5. The metal casing is covered with a first insulating layer, and then a third and fourth insulating layer, which provides double-layer insulation protection and improves reliability.

[0019] 6. The negative lead is connected to the bottom of the metal casing by laser welding to enhance the stability of the negative lead and ensure that the tantalum capacitor can be used in different environments;

[0020] 7. The connection between the metal outer shell cylinder and the cover plate adopts a stepped connection structure, which makes it easy to fix the position of the cover plate and ensures the welding seal.

[0021] 8. The positive and negative pins are arranged with their tips facing each other for easy external connection. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of this utility model;

[0023] Figure 2 This is a schematic diagram of the core structure of this utility model;

[0024] In the diagram: 1-Outer shell, 2-Conductive layer, 3-Core, 4-Second insulating layer, 5-Fixing ring, 6-Second solder joint, 7-Third insulating layer, 8-Lead wire, 9-First solder joint, 10-Positive lead, 11-Positive lead pad, 12-Negative lead pad, 13-Anode wire, 14-Insulating sheet, 15-Seventh solder joint, 16-Fourth insulating layer, 17-Negative lead, 18-Third solder joint, 19-First reinforcing post, 20-Fourth solder joint, 21-Second reinforcing post, 22-Fifth solder joint, 23-Stepped structure, 24-First insulating layer, 25-Oxide film layer, 26-First outer layer, 27-Second outer layer, 28-Third outer layer. Detailed Implementation

[0025] The technical solution of this utility model is further described below, but the scope of protection is not limited to what is described.

[0026] Example:

[0027] like Figure 1 , 2 As shown, a fully sealed surface-mount tantalum capacitor includes a housing 1, a core 3, and a cover plate. One side of the housing 1 is connected to the cover plate. A positive lead 10 and a negative lead 17 are provided on the outer wall of the housing 1. The core 3 is disposed inside the housing 1 and is connected to the inner wall of the housing 1 through a conductive layer 2. An anode wire 13 is provided on the core 3. One end of the anode wire 13 is connected to a lead wire 8. The lead wire 8 passes through the cover plate and is connected to the positive lead 10.

[0028] The outer casing 1 is made of metal; the lead wire 8 and the anode wire 13 are both tantalum wires; the positive electrode pin 10 and the negative electrode pin 17 are both L-shaped.

[0029] The conductive layer 2 is a conductive adhesive, and the tantalum core 3 is connected to the outer shell 1 through the conductive layer 2. After the adhesive is cured, its height is between one-half and three-quarters of the height of the tantalum core. In addition to having conductive properties, it also has the function of fixing the tantalum core 3.

[0030] The seventh solder joint 15 connecting the anode wire 13 and the lead wire 8 is located inside the metal casing 1. In order to maximize the solder joint strength of the anode wire 13 and the lead wire 8, the ends of the connection between the anode wire 13 and the lead wire 8 are flattened before connection.

[0031] The inner side of the outer shell 1 forms a stepped structure 23, which is connected to the cover plate. The stepped structure 23 and the cover plate cooperate to form an axial limiting structure.

[0032] The cover plate includes a second insulating layer 4 and a fixing ring 5. The second insulating layer 4 is connected to the outer shell 1 through the fixing ring 5. The fixing ring 5 and the outer shell 1 are welded to the second solder point 6 by a solder ring or laser welding. An insulating sheet 14 is provided on the anode wire 13, and the anode wire 13 passes through the insulating sheet 14. One side of the insulating sheet 14 is connected to the outer wall of the core 3. The second insulating layer 4 is a glass insulator. The lead hole of the cover plate and the lead wire 8 are sealed and insulated from the valve tube through the glass insulator. The insulating sheet 14 is a polytetrafluoroethylene sheet used to fix the anode wire 13.

[0033] The lead wire 8 passes through the second insulating layer 4 of the cover plate and then emerges from the lead wire hole of the cover plate and is soldered to the first solder point 9 with the positive electrode pin 10.

[0034] The core 3 is covered with a tantalum pentoxide dielectric oxide film layer 25. The oxide film layer 25 is covered with a first outer layer 26. A second outer layer 27 is disposed outside the first outer layer 26, and a third outer layer 28 is disposed outside the second outer layer 27. The first outer layer 26 is a manganese dioxide layer, serving as the cathode. The second outer layer 27 is a graphite layer, and the third outer layer 28 is a silver paste layer. The second outer layer 27 and the third outer layer 28 serve as auxiliary leads.

[0035] The outer wall of the housing 1 is provided with a positive electrode lead-out pad 11 and a negative electrode lead-out pad 12. The positive electrode lead-out pad 11 is connected to the positive electrode pin 10, and the negative electrode lead-out pad 12 is connected to the negative electrode pin 17. Both the positive electrode lead-out pad 11 and the negative electrode lead-out pad 12 are L-shaped.

[0036] The positive electrode lead-out pad 11 is connected to the outer wall of the outer casing 1 through the third insulating layer 7, and the negative electrode lead-out pad 12 is connected to the outer wall of the outer casing 1 through the fourth insulating layer 16. The negative electrode pin 17 is soldered to the outer casing 1 at the third solder point 18. The third insulating layer 7 is L-shaped, with the top edge of the folded edge extending between the positive electrode pin 10 and the cylindrical body of the metal outer casing 1. The fourth insulating layer 16 extends between the negative electrode lead-out pad 12 and the cylindrical body of the metal outer casing 1, providing double protection against short circuits between the positive and negative electrodes.

[0037] The cover plate is provided with a first reinforcing post 19 and a second reinforcing post 21. The positive electrode pin 10 is welded to the first reinforcing post 19 at a fourth solder point 20, and the positive electrode pin 10 is welded to the second reinforcing post 21 at a fifth solder point 22. Both the first reinforcing post 19 and the second reinforcing post 21 are made of metal and are used to reinforce the positive electrode pin 10.

[0038] The outer shell 1 is covered with a first insulating layer 24 from the positive end to the negative end. The first insulating layer 24 is outside the shell 1 and the cover plate. The first insulating layer 24 is mainly to prevent the positive and negative leads from short-circuiting each other. The lead wire 8 is welded to the positive lead 10 at the first solder point 9, and the anode wire 13 is welded to the lead wire 8 at the seventh solder point 15.

Claims

1. A hermetically-sealed chip tantalum capacitor characterized by: The device includes a shell (1), a core (3), and a cover plate. One side of the shell (1) is connected to the cover plate. The outer wall of the shell (1) is provided with a positive electrode pin (10) and a negative electrode pin (17). The core (3) is disposed inside the shell (1). The core (3) is connected to the inner wall of the shell (1) through a conductive layer (2). An anode wire (13) is disposed on the core (3). One end of the anode wire (13) is connected to a lead wire (8). The lead wire (8) passes through the cover plate and is connected to the positive electrode pin (10). The outer wall of the outer shell (1) is provided with a positive lead-out pad (11) and a negative lead-out pad (12). The positive lead-out pad (11) is connected to the positive lead (10), and the negative lead-out pad (12) is connected to the negative lead (17). The positive lead-out pad (11) is connected to the outer wall of the outer shell (1) through the third insulating layer (7), the negative lead-out pad (12) is connected to the outer wall of the outer shell (1) through the fourth insulating layer (16), and the negative lead (17) is soldered to the outer shell (1) at the third solder point (18). The outer side of the outer casing (1) is provided with a first insulating layer (24), the lead wire (8) is welded to the positive electrode pin (10) at the first solder point (9), and the anode wire (13) is welded to the lead wire (8) at the seventh solder point (15).

2. A hermetically sealed chip capacitor of claim 1, wherein: The inner side of the outer shell (1) forms a stepped structure (23), and the stepped structure (23) of the outer shell (1) is connected to the cover plate. The stepped structure (23) and the cover plate cooperate to form an axial limiting structure.

3. The fully sealed surface-mount tantalum capacitor as described in claim 1, characterized in that: The cover plate includes a second insulating layer (4) and a fixing ring (5). The second insulating layer (4) is connected to the outer shell (1) through the fixing ring (5). The fixing ring (5) is welded to the outer shell (1) at a second welding point (6). An insulating sheet (14) is provided on the anode wire (13). One side of the insulating sheet (14) is connected to the outer wall of the core (3).

4. A fully sealed surface-mount tantalum capacitor as described in claim 1, characterized in that: The core (3) is covered with an oxide film layer (25), the oxide film layer (25) is covered with a first outer layer (26), a second outer layer (27) is disposed outside the first outer layer (26), and a third outer layer (28) is disposed outside the second outer layer (27).

5. A fully sealed surface-mount tantalum capacitor as described in claim 1, characterized in that: The cover plate is provided with a first reinforcing post (19) and a second reinforcing post (21). The positive electrode pin (10) is welded to the first reinforcing post (19) at a fourth solder point (20), and the positive electrode pin (10) is welded to the second reinforcing post (21) at a fifth solder point (22).

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