Preparation method of ultra-low ESR high-energy hybrid tantalum capacitor and packaging structure of ultra-low ESR high-energy hybrid tantalum capacitor

Abstract

The invention provides a preparation process and a packaging structure of an ultra-low ESR high-energy hybrid tantalum capacitor. The tantalum capacitor is obtained by sequentially sintering, energizing, packaging, aging and the like after tantalum powder is pressed, the equivalent series resistance is small, and the equivalent series resistance can be roughly calculated according to the number of branches. The niobium shell and the cover plate are adopted, so that the weight of the product is reduced by 10.5 g; six slice tantalum cores are connected in parallel, the number of tantalum cores of the same shell can be increased, and equivalent resistance is reduced.

Description

Technical Field

[0001] The invention relates to a preparation method of an ultra-low ESR high-energy hybrid tantalum capacitor and a packaging structure thereof. Background Art

[0002] At present, domestic high-energy hybrid tantalum capacitors are developing rapidly. As the performance of high-energy hybrid tantalum capacitors becomes more and more stable and reliable, high-energy hybrid tantalum capacitors are widely used in the aerospace field, mainly used to realize the energy storage, filtering and other functions of power modules. As the working environment of high-end equipment becomes more and more complex, it is usually required that the equivalent series resistance (ESR) of the capacitor itself is small. Small ESR can increase the amount of current transmitted, reduce the voltage drop during discharge, and improve circuit performance. At the same time, in order to reduce the weight of the equipment, the capacitor is required to "reduce weight". Therefore, improving the ESR electrical performance parameters of high-energy hybrid tantalum capacitor products and reducing the weight of the capacitor body are particularly important for improving the maneuverability of aviation flight equipment. For example, the preparation method of the chip solid electrolyte tantalum capacitor disclosed in CN114360911B boils and washes the tantalum block after sintering, and then puts the carbon block into an energizing solution composed of phosphoric acid, ethylene glycol, deionized water and weak acid components for energization. However, the method used in the energizing process is to make constant current boost or constant power boost. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a preparation method of an ultra-low ESR high-energy hybrid tantalum capacitor and a packaging structure thereof.

[0004] The present invention is achieved through the following technical solutions.

[0005] The present invention provides a method for preparing an ultra-low ESR high-energy hybrid tantalum capacitor;

[0006] 1) 4870±10 mg of tantalum powder with a specific capacity of 17000 μF·V / g is loaded into a molding die, pressed into shape, and then slowly demolded to obtain an anode tantalum block;

[0007] 2) The anode tantalum block is sintered at a high temperature using a power of 60 kV·A. After the power is kept constant for 20 minutes, the sintering furnace is closed and the furnace is taken out after cooling to 30°C;

[0008] 3) Using ethylene glycol-phosphoric acid-water solution as the energizing solution, placing the sintered tantalum anode block into the energizing solution and energizing using an ascending voltage;

[0009] 4) Six anode tantalum blocks are connected in parallel and packaged into tantalum capacitors;

[0010] 5) Aging of the tantalum capacitor.

[0011] After the tantalum powder is loaded into the program mold, it is shaken to make the tantalum powder evenly distributed in the molding mold.

[0012] Said

[0013] The first stage of the boost voltage is 0-40V, and the boost current density is 0.008mA / g;

[0014] The second stage voltage of the boost voltage is 40-80V, and the boost current density is 0.006mA / g;

[0015] The third stage voltage of the boost voltage is 80-120V and the boost current density is 0.005mA / g.

[0016] When the voltage rises to 120V, maintain constant voltage for 4.5 hours.

[0017] A packaging structure of an ultra-low ESR high-energy hybrid tantalum capacitor, comprising an anode tantalum block, both upper and lower end surfaces of the anode tantalum block are covered with a layer of cathode sheet, a block spacer membrane is provided between adjacent anode tantalum blocks, six anode tantalum blocks are neatly stacked in an outer shell, an outer shell membrane is laid between the bottom of the outer shell and adjacent anode tantalum blocks, the side wall of the outer shell is covered with an insulating strip, a lower gasket is provided on the top anode tantalum block, the same side of each anode tantalum block is connected to one end of an inner electrode, the other end of the inner electrode is connected to a bus bar, one end of the bus bar is placed above the lower gasket and connected to a positive lead arranged in the center of the outer shell, the top opening of the outer shell is closed by an insulator cover plate, an insulating ring is provided between the lower gasket and the insulator cover plate, one end of the positive lead extends out of the insulator cover plate, and a cathode lead is also provided on the insulator cover plate.

[0018] The busbar is L-shaped, one end of which is placed on the side of the anode tantalum block where the inner electrode is installed, and the other end is placed between the lower gasket and the insulating ring. An adjustment gasket is also provided between the lower gasket and the insulating ring at the opposite end of the busbar, and an upper gasket is also provided between the adjustment gasket and the busbar and the insulating ring.

[0019] The bus bar is covered with an insulating sleeve, and the inner electrode extends into the insulating sleeve and is connected to the bus bar.

[0020] An opening protruding upward is processed at the center of the insulator cover plate, and the positive lead passes through the opening and is fixed by a sealant.

[0021] The shell is made of niobium alloy.

[0022] The insulator cover plate is a niobium insulator.

[0023] The beneficial effects of the present invention are: the equivalent series resistance is small, and the equivalent series resistance can be roughly calculated according to the number of branches. The niobium shell and cover plate are used, and the weight of the product is reduced by 10.5g. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1It is a structural schematic diagram of the present invention;

[0025] In the figure: 1-housing, 2-insulating strip, 3-cathode sheet, 4-housing diaphragm, 5-anode tantalum block, 6-block diaphragm, 7-adjusting gasket, 8-insulator cover, 9-sealant, 10-positive lead, 11-insulating ring, 12-cathode lead, 13-bus bar, 14-insulating ring, 15-upper gasket, 16-insulating sleeve, 17-lower gasket, 18-inner electrode. DETAILED DESCRIPTION

[0026] The technical solution of the present invention is further described below, but the scope of protection claimed is not limited to the description.

[0027] 1) Weigh 4870±10 mg of tantalum powder with a specific volume of 17000 μF·V / g using an electronic analytical balance, and form it using a 20.5×20.5 mm forming mold with a lubricant. Shake the tantalum powder evenly before forming to ensure uniform compacting density, and slowly demold to obtain an anode tantalum block with a certain strength;

[0028] 2) Sintering: Use a power of 60kV·A for high temperature sintering, keep it at temperature for 20 minutes, and take it out of the furnace after cooling to 30°C to ensure that the specific capacitance of the tantalum core and tantalum powder after sintering is about 17000μF·V / g.

[0029] 3) Conventional ethylene glycol-phosphoric acid-water solution was used for step-by-step voltage boosting. The boost current density at (0-40) V was 0.008 mA / g, the boost current density at (40-80) V was 0.006 mA / g, and the boost current density at (80-120) V was 0.005 mA / g. When the voltage reached 120 V, the voltage was maintained at a constant level for 4.5 hours to prepare a tantalum core with a good Ta2O5 dielectric oxide film.

[0030] 4) Six tantalum cores with Ta2O5 dielectric oxide films are assembled in parallel and laser welded using conventional packaging methods. Figure 1As shown, both upper and lower end surfaces of the anode tantalum block 5 are covered with a layer of cathode sheet 3, and block spacer membranes 6 are provided between adjacent anode tantalum blocks 5. Six anode tantalum blocks 5 are neatly stacked in the shell 1, and a shell diaphragm 4 is laid between the bottom of the shell 1 and the adjacent anode tantalum blocks 5. The side wall of the shell 1 is covered by an insulating strip 2, and a lower gasket 17 is provided on the anode tantalum block 5 at the top. The same side of each anode tantalum block 5 is connected to one end of the inner electrode 18, and the other end of the inner electrode 18 is connected to the bus bar 13. One end of the bus bar 13 is placed above the lower gasket 17 and connected to the positive lead 10 provided in the center of the shell 1. The top opening of the shell 1 is closed by an insulator cover 8, and an insulating ring 14 is provided between the lower gasket 17 and the insulator cover 8. One end of the positive lead 10 extends out of the insulator cover 8, and a cathode lead 12 is also provided on the insulator cover 8. By connecting six thin-film tantalum cores in parallel, the number of tantalum cores in the same shell can be increased. According to the resistance calculation method of the parallel circuit, Rtotal = R branches / number of C branches, so more tantalum cores are used.

[0031] The busbar 13 is L-shaped, with one end placed on the side of the anode tantalum block 5 where the inner electrode 18 is installed, and the other end placed between the lower gasket 17 and the insulating ring 14. An adjustment gasket 7 is also provided between the lower gasket 17 and the insulating ring 14 at the opposite end of the busbar 13, and an upper gasket 15 is also provided between the adjustment gasket 7 and the busbar 13 and the insulating ring 14.

[0032] The bus bar 13 is covered with an insulating sleeve 16 , and the inner electrode 18 extends into the insulating sleeve 16 and is connected to the bus bar 13 .

[0033] The center of the insulator cover plate 8 is processed with an opening protruding upward, and the positive lead 10 passes through the opening and is fixed by the sealant 9.

[0034] 5) Use conventional open aging and sealed aging procedures for aging.

[0035] Compared with the 80V4700μF high-energy hybrid tantalum capacitor with six thin tantalum cores connected in parallel, the ESR of the 80V4700μF high-energy hybrid tantalum capacitor prepared in the above embodiment is reduced from 0.37Ω to 0.2, and the ESR value is reduced by 46%. The weight is reduced from 62g to 51.3g, and the weight is reduced by 17%.

[0036] The capacitor prepared by the method of the present invention not only has the advantages of ultra-low ESR, but also has high capacitance accuracy, negative temperature capacitance change, and small leakage current. The electrical performance data are as follows:

[0037] Table 1: Parameters of 80V4700μF capacitor prepared by this method

[0038]

[0039] As can be seen from Table 1, the method of the present invention not only successfully manufactures high-energy hybrid tantalum capacitors with ultra-low ESR, but also the capacitors manufactured by the method have large capacitance, high precision, light weight, and small negative temperature capacitance change and leakage current.

Claims

1. A method for preparing an ultra-low ESR high-energy hybrid tantalum capacitor, characterized in that: 1) 4870±10 mg of tantalum powder with a specific capacity of 17000 μF·V / g is loaded into a molding die, pressed into shape, and then slowly demolded to obtain an anode tantalum block; 2) The anode tantalum block is sintered at a high temperature using a power of 60 kV·A. After the power is kept constant for 20 minutes, the sintering furnace is closed and the furnace is taken out after cooling to 30°C; 3) Using ethylene glycol-phosphoric acid-water solution as the energizing solution, placing the sintered tantalum anode block into the energizing solution and energizing using an ascending voltage; 4) Six anode tantalum blocks are connected in parallel and packaged into tantalum capacitors; 5) Aging of the tantalum capacitor.

2. The method for preparing the ultra-low ESR high-energy hybrid tantalum capacitor according to claim 1, characterized in that: After the tantalum powder is loaded into the program mold, it is shaken to make the tantalum powder evenly distributed in the molding mold.

3. The method for preparing the ultra-low ESR high energy hybrid tantalum capacitor according to claim 1, characterized in that: Said The first stage of the boost voltage is 0-40V, and the boost current density is 0.008mA / g; The second stage voltage of the boost voltage is 40-80V, and the boost current density is 0.006mA / g; The third stage voltage of the boost voltage is 80-120V and the boost current density is 0.005mA / g.

4. The method for preparing the ultra-low ESR high-energy hybrid tantalum capacitor according to claim 3, characterized in that: When the voltage rises to 120V, maintain constant voltage for 4.5 hours.

5. A packaging structure of an ultra-low ESR high-energy hybrid tantalum capacitor, used for packaging the tantalum capacitors according to claims 1 to 4, characterized in that: The invention comprises an anode tantalum block (5), wherein the upper and lower end surfaces of the anode tantalum block (5) are both covered with a layer of cathode sheet (3), a block spacing membrane (6) is provided between adjacent anode tantalum blocks (5), six anode tantalum blocks (5) are neatly stacked in an outer shell (1), an outer shell membrane (4) is laid between the bottom of the outer shell (1) and adjacent anode tantalum blocks (5), the side wall of the outer shell (1) is covered with an insulating strip (2), a lower gasket (17) is provided on the anode tantalum block (5) at the top, and the same side of each anode tantalum block (5) is in contact with an inner electrode (18). One end of the inner electrode (18) is connected to the positive electrode (10), and the other end of each inner electrode (18) is connected to a bus bar (13). One end of the bus bar (13) is placed above a lower gasket (17) and connected to a positive lead (10) provided at the center of the outer shell (1). The top opening of the outer shell (1) is closed by an insulator cover (8). An insulating ring (14) is provided between the lower gasket (17) and the insulator cover (8). One end of the positive lead (10) extends out of the insulator cover (8). A cathode lead (12) is also provided on the insulator cover (8).

6. The packaging structure of the ultra-low ESR high-energy hybrid tantalum capacitor according to claim 5, characterized in that: The bus bar (13) is L-shaped, one end of which is placed on the side of the anode tantalum block (5) on which the inner electrode (18) is installed, and the other end is placed between the lower gasket (17) and the insulating ring (14), and an adjustment gasket (7) is also provided between the lower gasket (17) and the insulating ring (14) at the end opposite to the bus bar (13), and an upper gasket (15) is also provided between the adjustment gasket (7) and the bus bar (13) and the insulating ring (14).

7. The packaging structure of the ultra-low ESR high-energy hybrid tantalum capacitor according to claim 5, characterized in that: The bus bar (13) is covered with an insulating sleeve (16), and the inner electrode (18) extends into the insulating sleeve (16) and is connected to the bus bar (13).

8. The packaging structure of the ultra-low ESR high-energy hybrid tantalum capacitor according to claim 5, characterized in that: The center of the insulator cover plate (8) is processed with an opening protruding upward, and the positive electrode lead (10) passes through the opening and is fixed by a sealant (9).

9. The packaging structure of the ultra-low ESR high-energy hybrid tantalum capacitor according to claim 5, characterized in that: The shell (1) is made of niobium alloy.

10. The packaging structure of the ultra-low ESR high-energy hybrid tantalum capacitor according to claim 5, characterized in that: The insulator cover plate (8) is a niobium insulator.

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