Metallized film capacitor positive and negative electrode differential metal spraying control method and device

Abstract

The invention relates to the technical field of metallized film capacitor manufacturing, and discloses a metallized film capacitor positive and negative electrode differential metal spraying control method and device. In order to solve the technical problems that in a traditional metal spraying process, the metal deposition amount of a positive electrode and the metal deposition amount of a negative electrode are unbalanced, electrode metal particles are not uniform, the loss tangent value (tan delta) of a capacitor is high, and fluctuation along with voltage is obvious, two metal spraying wires made of the same material are adopted; spraying to the end face of the capacitor core to form an electrode after melting by an arc spray gun; the core is a differential control mode that the wire feeding parameters of positive and negative electrode gold spraying wires are controlled, so that the wire feeding amount ratio of the positive and negative electrode gold spraying wires is 1: 1.15-1: 1.22, and the positive and negative electrode metal deposition amount is balanced. Experiments prove that under the conditions of 1kHz, 25 DEG C and 50% RH, the tan delta of the capacitor prepared by the method is stably maintained in a range of 0.009%-0.013%, the electrode reliability is high, the use requirements of high rated current and low loss can be met, and the capacitor is remarkably superior to a traditional process.

Description

Technical Field

[0001] This invention relates to the field of metallized film capacitor manufacturing technology, and in particular to a method and apparatus for controlling the differential gold spraying of the positive and negative electrodes of a metallized film capacitor, specifically applicable to production scenarios that improve electrode uniformity and reduce capacitor loss through arc gold spraying process. Background Technology

[0002] Metallized film capacitors are widely used in power electronics, new energy, and communications due to their advantages such as high rated voltage, low loss, and long lifespan. The electrode performance directly determines the capacitor's core indicators, including rated current, loss level, and stability. As a crucial step in the preparation of metallized film capacitor electrodes, the gold sputtering process directly affects the uniformity and deposition stability of the metal particles, thus determining the overall performance of the capacitor.

[0003] In existing gold spraying processes, arc gold spraying technology is commonly used: two gold spraying wires of the same material (mostly pure zinc) are selected as the positive and negative electrodes, respectively. They are fed to the arc spray gun at the same speed by a wire feeding mechanism. When the two gold spraying wires collide, an electric arc is generated. The metal wires are melted using Joule heating, and then the molten metal particles are blown onto the end face of the capacitor core by high-pressure gas, ultimately forming the electrodes. The core design logic of this process is "symmetric control," which assumes that the same wire diameter and the same wire feeding speed can achieve a balance in the amount of metal deposited on the positive and negative electrodes.

[0004] However, through extensive experiments, the applicant discovered that the "symmetric control" of the traditional process has a fatal flaw: during the arc spraying process, there is a significant temperature difference between the positive and negative electrode regions (under the normal operating parameters of 100A current and 22V voltage, the temperature on the cathode side (negative electrode) is 700~750℃, and the temperature on the anode side (positive electrode) is 650~700℃). The temperature of the negative electrode is significantly higher than that of the positive electrode, resulting in a much greater melting loss rate of the gold wire sprayed on the negative electrode than that on the positive electrode. Under the control method of "same wire diameter + same wire feed speed", the amount of positive and negative electrode metal deposition will inevitably be unbalanced, which will eventually manifest as uneven distribution of gold-sprayed particles (negative electrode droplet size 10~15μm, positive electrode droplet size 10~20μm and containing a large number of incompletely melted particles). This will lead to a high loss tangent (tanδ) of the capacitor, which fluctuates significantly with the increase of charge and discharge voltage (tanδ can increase from 0.01% to more than 0.08% in traditional processes). This seriously affects the applicability and stability of the capacitor in high voltage and high rated current scenarios. This problem has long plagued those skilled in the art but has not been effectively solved. Summary of the Invention

[0005] In view of the above-mentioned defects of the prior art, the present invention aims to solve the technical problem that the control method of "same wire diameter + same wire feed speed" in the traditional gold spraying process leads to an imbalance in the amount of positive and negative electrode metal deposition and uneven electrode metal particles, which in turn causes the capacitor loss tangent (tanδ) to be too high and fluctuate significantly with the increase of voltage.

[0006] To achieve the above objectives, the present invention provides a method and corresponding device for differential gold sputtering control of the positive and negative electrodes of a metallized thin film capacitor. The core technical concept is: based on the difference in melting loss caused by the temperature difference between the positive and negative electrodes, the loss difference is compensated by "differentiated wire feeding parameter control" to maintain the amount of metal wire fed to the positive and negative electrodes in the optimal ratio range, thereby balancing the deposition amount and improving the electrode uniformity.

[0007] This invention provides a method for controlling the differential gold sputtering of the positive and negative electrodes of a metallized thin-film capacitor, comprising the following steps:

[0008] Two gold-plated wires of the same material are used. The gold-plated wires are melted by an electric arc spray gun and sprayed onto the end face of the capacitor core to form electrodes.

[0009] The feeding parameters of the two gold-plated wires are controlled so that the ratio of the feeding amount of the positive electrode gold-plated wire to the negative electrode gold-plated wire is 1:1.15 to 1:1.22, so as to balance the amount of positive and negative electrode metal deposition and improve the uniformity of electrode metal particles.

[0010] Preferably, the wire feeding parameters of the two gold sputtering wires are controlled so that the ratio of the wire feeding amount of the positive electrode gold sputtering wire to that of the negative electrode gold sputtering wire is 1:1.18, so as to balance the amount of positive and negative electrode metal deposition and improve the uniformity of electrode metal particles.

[0011] Preferably, the wire feeding parameters include the wire feeding speed. When the diameters of the positive electrode gold sputtering wire and the negative electrode gold sputtering wire are the same, the wire feeding speed of the negative electrode gold sputtering wire is 1.15 to 1.22 times that of the positive electrode gold sputtering wire.

[0012] Preferably, the wire feeding parameters include the wire feeding speed. When the diameters of the positive electrode gold sputtering wire and the negative electrode gold sputtering wire are the same, the wire feeding speed of the negative electrode gold sputtering wire is 1.18 times that of the positive electrode gold sputtering wire.

[0013] Preferably, the wire feeding parameters include wire diameter. When the wire feeding speeds of the positive electrode gold-plated wire and the negative electrode gold-plated wire are the same, the wire diameter of the negative electrode gold-plated wire is 1.07 to 1.10 times that of the positive electrode gold-plated wire.

[0014] Preferably, the wire feeding parameters include wire diameter. When the wire feeding speeds of the positive electrode gold-plated wire and the negative electrode gold-plated wire are the same, the wire diameter of the negative electrode gold-plated wire is 1.09 times that of the positive electrode gold-plated wire.

[0015] Preferably, the difference in wire feeding speed between the positive electrode gold sputtering wire and the negative electrode gold sputtering wire does not exceed 25%.

[0016] Preferably, the gold-sprayed wire is made of pure zinc or a zinc-tin alloy.

[0017] Preferably, the operating parameters of the electric arc spray gun are: current 90~110A, voltage 18~24V.

[0018] Preferably, the operating parameters of the electric arc spray gun are: current 100A, voltage 22V.

[0019] Another aspect of the present invention provides a device for differential gold sputtering of the positive and negative electrodes of a metallized thin film capacitor, including an arc spray gun, two sets of wire feeding mechanisms and a capacitor core clamp.

[0020] The two sets of wire feeding mechanisms are respectively used to feed the positive electrode gold-plated wire and the negative electrode gold-plated wire to the arc spray gun, and the wire feeding mechanism can adjust the wire feeding speed or the diameter of the gold-plated wire being fed.

[0021] The arc spray gun is used to melt the received gold-sprayed wire and blow the molten metal particles onto the end face of the capacitor core fixed by the capacitor core clamp using gas to form electrodes.

[0022] The adjustment accuracy of the wire feeding mechanism is such that the ratio of the wire feeding amount of the positive electrode gold sputtering wire to that of the negative electrode gold sputtering wire is 1:1.15 to 1:1.22.

[0023] Preferably, the adjustment accuracy of the wire feeding mechanism satisfies the following condition: the ratio of the wire feeding amount of the positive electrode gold sputtering wire to that of the negative electrode gold sputtering wire is 1:1.18.

[0024] Preferably, the wire feeding mechanism includes a speed adjustment module. When the diameters of the positive and negative gold-plated wires being fed are the same, the speed adjustment module can adjust the wire feeding speed of the negative gold-plated wire to 1.15 to 1.22 times that of the positive gold-plated wire.

[0025] Preferably, the wire feeding mechanism includes a speed adjustment module. When the diameters of the positive and negative gold-plated wires being fed are the same, the speed adjustment module can adjust the wire feeding speed of the negative gold-plated wire to 1.18 times the wire feeding speed of the positive gold-plated wire.

[0026] Preferably, the wire feeding mechanism includes a wire diameter adaptation module. When the wire feeding speeds of the positive and negative electroplated wires are the same, the wire diameter adaptation module can make the wire diameter of the conveyed negative electroplated wire 1.07 to 1.10 times that of the positive electroplated wire.

[0027] Preferably, the wire feeding mechanism includes a wire diameter adaptation module. When the wire feeding speeds of the positive and negative electroplated wires are the same, the wire diameter adaptation module can make the wire diameter of the conveyed negative electroplated wire 1.09 times that of the positive electroplated wire.

[0028] Preferably, it also includes a parameter monitoring module for monitoring the difference in wire feeding speed between the positive and negative electrode gold sputtering wires, ensuring that the difference does not exceed 25%.

[0029] This invention achieves the following technical effects through precise control of differentiated wire feeding parameters and a reasonable range of arc spray gun operating parameters:

[0030] Electrode uniformity is significantly improved: within the working range of 90~110A current and 18~24V voltage of the arc spray gun, combined with a wire feed ratio of 1:(1.15~1.22), the amount of metal deposited on both the positive and negative electrodes can be balanced, the particle size distribution of the gold sprayed particles is concentrated (D50 is stable at 9~12μm, standard deviation ≤4.5), and there are no obvious unmelted particles.

[0031] Significantly optimized loss characteristics: Under conditions of 1kHz, 25℃, and 50%RH, regardless of whether speed differentiation or wire diameter differentiation control is used, the tanδ of the capacitor is stably maintained in the range of 0.009%~0.013%, and the fluctuation is minimal in a wide voltage range of 0~900VAC, which is significantly better than traditional processes (tanδ increases to over 0.08% with increasing voltage).

[0032] High process stability: The working parameter range of the arc spray gun (90~110A, 18~24V) ensures stable arc combustion and avoids uneven melting caused by current and voltage fluctuations. At the same time, by limiting the wire feeding speed difference to ≤25%, combined with a speed ratio range of 1.15~1.22 times (the actual maximum speed difference is 22%), the side effects of differential control, such as arc blow, wire jamming, and material oxidation, are completely avoided, ensuring continuous and stable production.

[0033] Wide adaptability: It provides two differentiated control modes, a wide range of parameter matching intervals, and a reasonable range of arc spray gun working parameters. It does not require large-scale modification of existing gold spraying equipment. The parameter combination can be flexibly selected according to the production scenario (such as the speed adjustment accuracy of existing equipment, wire diameter supply, and equipment power adaptability), reducing the transformation cost of enterprises and improving process compatibility.

[0034] The following will further explain the concept, specific structure, and technical effects of the present invention in conjunction with the accompanying drawings, so as to fully understand the purpose, features, and effects of the present invention. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the spray gold process;

[0036] In the diagram: 1. Electrode clamp - positive electrode; 2. Gas storage device; 3. Electrode clamp - negative electrode; 4. Metal wire - negative electrode; 5. Metal particles; 6. Electric arc; 7. Blown gas; 8. Metal wire - positive electrode;

[0037] Figure 2 The graph shows the relationship between charging / discharging voltage and 1kHz tanδ (before and after changing the wire feed speed).

[0038] In the figure: Dashed line: Without changing the negative electrode wire feeding speed, the tanδ value increases significantly with increasing voltage, from 0.01% to 0.08%; Solid line: After changing the negative electrode wire feeding rate, the negative electrode wire feeding speed is 1.18 times that of the positive electrode, and the tanδ value is relatively stable, maintaining in the range of 0.009-0.012%.

[0039] Figure 3 The graph shows the relationship between charge / discharge voltage and 1kHz tanδ (before and after changing the wire diameter).

[0040] In the figure: Dashed line: Without changing the diameter of the negative electrode wire, the tanδ value increases significantly with increasing voltage, from 0.01% to 0.082%; Solid line: After changing the diameter of the negative electrode wire, the diameter of the negative electrode wire is 1.09 times that of the positive electrode, and the tanδ value is relatively stable, maintaining in the range of 0.01-0.013%. Detailed Implementation

[0041] The following description, with reference to the accompanying drawings, illustrates several preferred embodiments of the present invention to make its technical content clearer and easier to understand. The present invention can be embodied in many different forms, and the scope of protection of the present invention is not limited to the embodiments mentioned herein.

[0042] In the accompanying drawings, components with the same structure are indicated by the same numerical designation, and components with similar structures or functions are indicated by similar numerical designations. The dimensions and thicknesses of each component shown in the drawings are arbitrary, and the present invention does not limit the dimensions and thicknesses of each component. To make the illustrations clearer, the thickness of some components has been appropriately exaggerated in the drawings.

[0043] To achieve the above objectives, the present invention provides a method and corresponding device for differential gold sputtering control of the positive and negative electrodes of a metallized thin film capacitor. The core technical concept is: based on the difference in melting loss caused by the temperature difference between the positive and negative electrodes, the loss difference is compensated by "differentiated wire feeding parameter control" to maintain the amount of metal wire fed to the positive and negative electrodes in the optimal ratio range, thereby balancing the deposition amount and improving the electrode uniformity.

[0044] 1. Differential gold plating control method for positive and negative electrodes of metallized film capacitors

[0045] Basic process: Two gold-plating wires of the same material (pure zinc or zinc-tin alloy) are used. The gold-plating wires are melted by an electric arc spray gun (operating parameters: current 90~110A, voltage 18~24V). High-pressure gas is used to spray metal particles onto the end face of the capacitor core to form electrodes.

[0046] Core control: Adjust the wire feeding parameters of the two gold-plated wires to strictly control the ratio of the positive to negative gold-plated wire feed amounts to 1:1.15~1:1.22. The wire feeding parameters include wire feeding speed and wire diameter, and can be implemented in one of the following two ways:

[0047] (1) When the diameters of the positive and negative gold-plated wires are the same, the wire feeding speed of the negative gold-plated wire should be controlled to be 1.15 to 1.22 times that of the positive gold-plated wire.

[0048] (2) When the wire feeding speed of the positive and negative electrode gold sputtering wires is the same, the wire diameter of the negative electrode gold sputtering wire is controlled to be 1.07 to 1.10 times that of the positive electrode gold sputtering wire.

[0049] Process constraints: The difference in wire feeding speed between the positive and negative electrodes for gold spraying must not exceed 25% to avoid exacerbating arc blow, excessive oxidation of zinc wire, or wire jamming caused by material softening.

[0050] In other embodiments, this method also features a dynamic environmental adaptive adjustment function. By monitoring the temperature (5℃~45℃), humidity (30% RH~70% RH), and air source pressure (0.4MPa~0.6MPa) of the gold spraying environment in real time, it automatically fine-tunes the wire feeding parameters and the arc spray gun operating parameters to ensure optimal gold spraying results are maintained under different environmental conditions. The specific adjustment logic is as follows:

[0051] When the ambient temperature rises by 5°C, the current of the arc spray gun is automatically reduced by 2A, and the wire feeding speed of the negative electrode is increased by 0.5% to avoid increased melting loss of the negative electrode due to the rise in ambient temperature.

[0052] When the ambient humidity increases by 10% RH, the tin mass fraction in the zinc-tin alloy gold-plated wire is automatically increased by 0.5% (achieved by replacing the gold-plated wire with the corresponding specification), or the wire feeding ratio is increased by 0.3% when the pure zinc wire material is maintained, thereby enhancing the electrode's resistance to moisture and oxidation.

[0053] When the gas source pressure fluctuates by 0.05 MPa, the wire feeding speed is automatically adjusted by ±1% to compensate for the impact of airflow speed changes on droplet delivery and ensure the stable deposition density of metal particles on the core end face.

[0054] This dynamic adaptive mechanism breaks through the stringent environmental requirements of traditional spray gold processes, expanding the range of applicable environments for the process. It can stably produce high-performance capacitors in production workshops in different regions and seasons without the need for frequent manual parameter adjustments, thus improving production efficiency and product consistency.

[0055] 2. Differentiated gold spraying device for positive and negative electrodes of metallized film capacitors

[0056] The device is used to perform the above method and includes an arc spray gun, two sets of wire feeding mechanisms, a capacitor core clamp, and a parameter monitoring module.

[0057] Arc spray gun: A conventional arc gold spray gun is used, with working parameters set to current 90~110A and voltage 18~24V. This parameter range can ensure stable arc combustion, fully melt the gold wire, and maintain a temperature difference of 50~100℃ between the positive and negative electrode areas (to meet the compensation premise of melting loss difference). It is used to receive the gold wire fed by the wire feeding mechanism, melt the gold wire through the arc, and blow metal particles onto the end face of the capacitor core with high pressure gas.

[0058] Wire feeding mechanism: Two sets of wire feeding mechanisms correspond to the positive and negative electrodes respectively for gold sputtering. Each set includes a speed adjustment module and a wire diameter matching module: The speed adjustment module can precisely adjust the wire feeding speed, and the adjustment accuracy meets the control requirements of "1.15~1.22 times ratio"; The wire diameter matching module can adapt to gold sputtering wires of different diameters to ensure a precise match of "1.07~1.10 times wire diameter".

[0059] Capacitor core clamp: Used to fix the capacitor core, ensuring that the end face of the core is perpendicular to the spray gun spray direction, and ensuring that the metal particles are evenly adhered;

[0060] Parameter monitoring module: Real-time monitoring of the wire feeding speed of the positive and negative electrode gold sputtering wires. When the speed difference approaches 25%, an early warning is issued to avoid process abnormalities.

[0061] This invention clearly reveals the quantitative relationship between "temperature difference between positive and negative electrodes → melting loss difference → deposition imbalance" in the process of arc gold spraying, breaking the inherent understanding of "symmetric control" in traditional processes and providing a core theoretical basis for problem solving;

[0062] This invention, through extensive orthogonal experiments covering wire feed speed ratios of 1.10 to 1.25, wire diameter ratios of 1.05 to 1.12, arc gun currents of 80 to 120 A, and voltages of 16 to 26 V, precisely screened out multi-dimensional effective parameter ranges—wire feed ratios of 1:1.15 to 1:1.22, speed ratios of 1:1.15 to 1:1.22, wire diameter ratios of 1.07 to 1.10, arc gun currents of 90 to 110 A, and voltages of 18 to 24 V. This demonstrates that the goal of minimizing losses can be achieved within this combined range, rather than relying on a single value. This represents a breakthrough from "single-point control" to "multi-parameter collaborative range control," significantly expanding the applicability of the process.

[0063] This invention, through extensive experiments, derives the optimal ratio for gold plating on the positive and negative electrodes to achieve the minimum and most stable dielectric loss value:

[0064]

[0065] in, The diameter of the negative electrode wire; The diameter of the positive electrode wire; This refers to the negative electrode wire feeding rate; ρ is the positive electrode wire feeding rate; t is the conveying time; ρ is the dielectric loss ratio.

[0066] Therefore, when hour,

[0067]

[0068] when hour,

[0069]

[0070] This invention, through experimental verification, determines the compatibility of "wire feed speed difference ≤ 25%" with a speed ratio of 1.15~1.22 times. At the same time, it clarifies the matching relationship between the arc gun operating parameters and the melting efficiency and temperature difference of the gold-sprayed wire. This ensures the effect of differential compensation while avoiding secondary technical problems such as arc instability and insufficient melting caused by excessive parameter deviation, thus ensuring the practicality and operability of the solution.

[0071] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and preferred embodiments. The scope of protection of the present invention is not limited to the following embodiments.

[0072] Example 1: Spray coating control based on differentiated wire feed speed (same wire diameter)

[0073] 1. Equipment Configuration

[0074] Using the aforementioned gold spraying device, the working parameters of the arc spray gun are set to a current of 90~110A and a voltage of 18~24V (three sets of typical parameters are selected in this embodiment: Group 1: 90A / 18V; Group 2: 100A / 22V; Group 3: 110A / 24V); the wire feeding mechanism uses pure zinc gold spraying wire with a wire diameter of 1mm; the capacitor core clamp fixes a 10μF metallized film capacitor core.

[0075] 2. Parameter settings

[0076] Through the speed adjustment module of the wire feeding mechanism, three different speed ratios can be set for each set of arc gun parameters:

[0077] Group 1 (90A / 18V): Positive electrode wire feeding speed 8m / min, negative electrode wire feeding speed 9.2m / min (1.15 times), 9.45m / min (1.18 times), 9.76m / min (1.22 times), speed difference 15%~22%;

[0078] Group 2 (100A / 22V): Positive electrode wire feeding speed 8m / min, negative electrode wire feeding speed 9.2m / min (1.15 times), 9.45m / min (1.18 times), 9.76m / min (1.22 times), speed difference 15%~22%;

[0079] Group 3 (110A / 24V): Positive electrode wire feeding speed 8m / min, negative electrode wire feeding speed 9.2m / min (1.15 times), 9.45m / min (1.18 times), 9.76m / min (1.22 times), with a speed difference of 15%~22%.

[0080] 3. Work Process

[0081] (1) Start the device, fix the capacitor core with the capacitor core clamp and adjust it to the designated position;

[0082] (2) Two sets of wire feeding mechanisms feed gold-sprayed wires to the arc spray gun at a set speed. The two gold-sprayed wires collide in the spray gun to generate an electric arc. Within the parameter range of 90~110A and 18~24V, the temperature of the negative electrode area is maintained at 680~760℃, and the temperature of the positive electrode area is maintained at 630~710℃, still maintaining a temperature difference of 50~100℃.

[0083] (3) The gold-sprayed wire is fully melted under the action of the electric arc to form metal droplets. The high-pressure gas blows the droplets onto the end face of the capacitor core. Since the wire feeding speed of the negative electrode is 1.15 to 1.22 times that of the positive electrode, it compensates for its higher melting loss rate, and the metal deposition amount of the positive and negative electrodes tends to be consistent.

[0084] (4) The parameter monitoring module monitors the wire feeding speed in real time. The speed difference of all experimental groups is ≤22%, and there is no abnormal warning.

[0085] 4. Experimental Results

[0086] The test data of all experimental groups under the conditions of 1kHz, 25℃, and 50%RH met the following requirements: the D50 of the metal particles was 9~12μm, the standard deviation was ≤4.5, and the tanδ of the capacitor was 0.009%~0.013%. After 10 charge-discharge cycles of 0~900VAC, the tanδ showed no significant fluctuation, proving that the working parameter range of the arc gun (90~110A, 18~24V) and the wire feed speed ratio range were effectively coordinated.

[0087] Example 2: Spray coating control based on differentiated wire diameter (same wire feed speed)

[0088] 1. Equipment Configuration: The aforementioned gold spraying device is used. The working parameters of the arc spray gun are set to a current of 90~110A and a voltage of 18~24V (three sets of typical parameters are selected in this embodiment: Group 1: 90A / 18V; Group 2: 100A / 22V; Group 3: 110A / 24V); the wire feeding speed of the wire feeding mechanism is set to 6m / min; the capacitor core clamp is used to fix a 10μF metallized film capacitor core.

[0089] 2. Parameter settings

[0090] Using the wire diameter adaptation module of the wire feeding mechanism, pure zinc gold-plated wire is selected, and three different wire diameter ratios are set for each set of arc gun parameters:

[0091] Group 1 (90A / 18V): Positive electrode wire diameter 1.6mm, negative electrode wire diameter 1.712mm (1.07 times), 1.744mm (1.09 times), 1.76mm (1.10 times).

[0092] Group 2 (100A / 22V): Positive electrode wire diameter 1.6mm, negative electrode wire diameter 1.712mm (1.07 times), 1.744mm (1.09 times), 1.76mm (1.10 times).

[0093] Group 3 (110A / 24V): Positive electrode wire diameter 1.6mm, negative electrode wire diameter 1.712mm (1.07 times), 1.744mm (1.09 times), 1.76mm (1.10 times).

[0094] 3. Work process:

[0095] (1) Start the device, fix the capacitor core and adjust its position;

[0096] (2) Two sets of wire feeding mechanisms feed gold-sprayed wires of different diameters at a speed of 6m / min. The gold-sprayed wires collide in the spray gun to generate an electric arc. Within the parameter range of 90~110A and 18~24V, the gold-sprayed wires are fully melted. The negative electrode wire diameter is larger, the resistance is smaller, the current flowing through is relatively reduced, and the melting loss rate is reduced.

[0097] (3) High-pressure gas blows the molten metal droplets onto the end face of the core, balancing the amount of positive and negative electrode metal deposition to form a uniform electrode.

[0098] 4. Experimental Results

[0099] The test data of all experimental groups under the conditions of 1kHz, 25℃, and 50%RH all met the following requirements: metal particle D50 was 9.5~12μm, standard deviation ≤4.5, and capacitor tanδ was 0.009%~0.013%. After 10 charge-discharge cycles of 0~900VAC, the tanδ stability was excellent, proving that the working parameter range of the arc gun and the wire diameter ratio range worked together effectively.

[0100] Comparative Example 1

[0101] Capacitors of the same specifications were prepared using traditional processes (same wire diameter 1mm, same wire feeding speed 8m / min, arc gun parameters 100A / 22V). Under the same experimental conditions, the metal particle D50 was found to be 15μm, with a standard deviation of 5.4 and a tanδ of 0.07%. When the charge / discharge voltage was increased to 900VAC, the tanδ increased to 0.08%, which was significantly worse than the combined effect of all parameters in Examples 1 and 2 of this invention, fully demonstrating the technical advantages of this invention.

[0102] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A method for controlling the differential gold sputtering of the positive and negative electrodes of a metallized thin-film capacitor, characterized in that, Includes the following steps: Two gold-plated wires of the same material are used. The gold-plated wires are melted by an electric arc spray gun and sprayed onto the end face of the capacitor core to form electrodes. The feeding parameters of the two gold-plated wires are controlled so that the ratio of the feeding amount of the positive electrode gold-plated wire to the negative electrode gold-plated wire is 1:1.15 to 1:1.22, so as to balance the amount of positive and negative electrode metal deposition and improve the uniformity of electrode metal particles.

2. The method as described in claim 1, characterized in that, The wire feeding parameters include the wire feeding speed. When the diameters of the positive electrode gold sputtering wire and the negative electrode gold sputtering wire are the same, the wire feeding speed of the negative electrode gold sputtering wire is 1.15 to 1.22 times that of the positive electrode gold sputtering wire.

3. The method as described in claim 1, characterized in that, The wire feeding parameters include wire diameter. When the wire feeding speeds of the positive electrode gold-plated wire and the negative electrode gold-plated wire are the same, the wire diameter of the negative electrode gold-plated wire is 1.07 to 1.10 times that of the positive electrode gold-plated wire.

4. The method as described in claim 2, characterized in that, The difference in wire feeding speed between the positive electrode gold-plated wire and the negative electrode gold-plated wire does not exceed 25%.

5. The method according to any one of claims 1-4, characterized in that, The gold-sprayed wire is made of pure zinc or a zinc-tin alloy.

6. The method according to any one of claims 1-4, characterized in that, The operating parameters of the electric arc spray gun are: current 90~110A, voltage 18~24V.

7. A device for differential gold sputtering of the positive and negative electrodes of a metallized thin-film capacitor, characterized in that, Includes an electric arc spray gun, two sets of wire feeding mechanisms, and capacitor core clamps; The two sets of wire feeding mechanisms are respectively used to feed the positive electrode gold-plated wire and the negative electrode gold-plated wire to the arc spray gun, and the wire feeding mechanism can adjust the wire feeding speed or the diameter of the gold-plated wire being fed. The arc spray gun is used to melt the received gold-sprayed wire and blow the molten metal particles onto the end face of the capacitor core fixed by the capacitor core clamp using gas to form electrodes. The adjustment accuracy of the wire feeding mechanism is such that the ratio of the wire feeding amount of the positive electrode gold sputtering wire to that of the negative electrode gold sputtering wire is 1:1.15 to 1:1.

22.

8. The apparatus as claimed in claim 7, characterized in that, The wire feeding mechanism includes a speed adjustment module. When the diameters of the positive and negative gold-plated wires being fed are the same, the speed adjustment module can adjust the wire feeding speed of the negative gold-plated wire to 1.15 to 1.22 times that of the positive gold-plated wire.

9. The apparatus as claimed in claim 7, characterized in that, The wire feeding mechanism includes a wire diameter adaptation module. When the wire feeding speeds of the positive and negative electroplated wires are the same, the wire diameter adaptation module can make the wire diameter of the conveyed negative electroplated wire 1.07 to 1.10 times that of the positive electroplated wire.

10. The apparatus as claimed in claim 7, characterized in that, It also includes a parameter monitoring module, which monitors the difference in wire feeding speed between the positive and negative electrode gold sputtering wires to ensure that the difference does not exceed 25%.

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