Rapid detection device and method for hydration resistance of low-voltage aluminum electrolytic capacitor

Abstract

This invention belongs to the field of electrolytic capacitor testing technology, specifically relating to a rapid testing device and method for the hydration resistance of low-voltage aluminum electrolytic capacitors. The device includes a reflux device comprising a base, an oil bath, a double-necked flask, and a serpentine condenser. A support rod is fixedly mounted on top of the base. A screw block is threaded onto the outer side of the support rod. A support rod is integrally formed on one side of the screw block, and a tray is integrally formed at one end of the support rod. The serpentine condenser is connected to the top of the double-necked flask, and a limiting block is integrally formed on the outer side of its upper end. The limiting block is in contact with the upper surface of the tray. This invention can simulate the long-term hydration failure process of capacitors in a short time, significantly reducing the testing time. It also precisely controls the shaking amplitude, avoiding problems such as flask cracking, seal failure, and uneven water distribution, thus improving testing safety, stability, and accuracy without changing the original testing and judgment standards, closely conforming to the actual aging and failure mechanism of capacitors.

Description

Technical Field

[0001] This invention belongs to the field of electrolytic capacitor testing technology, specifically relating to a rapid testing device and method for the hydration resistance of low-voltage aluminum electrolytic capacitors. Background Technology

[0002] The lifespan and reliability of low-voltage aluminum electrolytic capacitors are closely related to their key materials—anode foil, cathode foil, and electrolyte. The electrolyte typically contains a significant amount of water to improve conductivity and oxide film repair capabilities. However, during long-term use, this water can react with the alumina film on the anode and cathode foil surfaces, forming hydrated alumina with poor performance. This leads to capacitor capacity decay, increased loss tangent, and elevated leakage current, ultimately resulting in failure and significantly shortening the capacitor's lifespan.

[0003] In existing technologies, the hydration resistance of aluminum foil is typically evaluated using two methods: one is to assemble the material into a finished capacitor and then conduct a high-temperature storage life test (e.g., Lower storage The first method is time-consuming and costly (requiring the production of a sufficient quantity of finished capacitors); the second method involves immersing the electrode foil in an electrolyte solution at a high temperature (at least...). Under short time (not exceeding) Sealed storage test. Although this method is faster than the traditional long-term life test of intact capacitors, it is not specific enough for low-voltage aluminum electrolytic capacitors with high water content in the electrolyte, and still has the problem of long test cycle (requiring several weeks), which makes it difficult to meet the needs of rapid industrial testing and rapid matching of raw materials.

[0004] Furthermore, the actual testing process suffers from several technical defects: First, traditional condensation structures can only form scattered water vapor or intermittent water films, failing to form a continuous and complete liquid water film on the capacitor casing, leads, and oxide film surface. This easily leads to problems such as surface drying and dehydration, and hydrophobic dead zones. Water molecules cannot fully wet the gaps in the plastic seal and the micropores of the aluminum foil oxide film, resulting in a slow hydration degradation reaction process and an extremely long testing cycle, which cannot meet the industry's demand for rapid testing. Second, existing devices lack dynamic adjustment mechanisms, with fixed positions for the flask and condenser tube. The top condensate cannot drip evenly and promptly, and the hydration reaction is prone to stalling midway. Moreover, it is impossible to accelerate the reaction through micro-positive pressure, forced convection, or other means. The simulated failure process deviates significantly from the actual long-term aging mechanism of the capacitor, resulting in insufficient accuracy of the test results. Third, some testing devices with shaking structures cannot accurately control the shaking amplitude and frequency, easily leading to safety issues such as flask explosion and seal failure. This also causes disordered steam return paths, uneven condensate spraying, and some capacitors failing to effectively contact the water film, resulting in test failure and poor testing stability and safety.

[0005] In summary, existing capacitor hydration failure detection technologies struggle to balance detection efficiency, result accuracy, and operational safety, and cannot accurately simulate the real hydration failure process in a short time. This restricts the development and practical application of capacitor detection technology. Therefore, developing a device that can quickly, stably, and accurately detect capacitor hydration failure has become an urgent technical problem to be solved in this field. Summary of the Invention

[0006] The purpose of this invention is to provide a rapid testing device and method for the hydration resistance of low-voltage aluminum electrolytic capacitors, so as to solve the problems mentioned in the background art.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a rapid testing device and method for the hydration resistance of low-voltage aluminum electrolytic capacitors, comprising a reflux device, the reflux device including a base, an oil bath, a double-necked flask, and a serpentine condenser tube; a support rod is fixedly installed above the base; a screw block is threaded to the outer side of the support rod; a support rod is integrally formed on one side of the screw block; a tray is integrally formed at one end of the support rod; the serpentine condenser tube is connected to the top of the double-necked flask, and a limiting block is integrally formed on the outer side of its upper end; the limiting block and the upper surface of the tray... The components are in contact with each other and are used to limit the serpentine condenser tube. The upper and lower ends of the serpentine condenser tube are respectively provided with water inlet and water outlet, and the cooling liquid is circulated through the water inlet and water outlet. The oil bath is placed above the base, and the double-necked flask is placed inside the oil bath. The outer side of the limiting block is integrally formed with a trapezoidal block. The support rod is through-shaped and the inner wall is slidably connected with a hydraulic rod. The outer end of the hydraulic rod is integrally formed with a collar, and the inner wall of the collar is rolled with a ball. The ball contacts the outer surface of the trapezoidal block. The left end of the support rod is connected to an external hydraulic pump pipeline.

[0008] The present invention further illustrates that the outer surface of the limiting block is provided with a groove, the upper surface of the tray is integrally formed with a locking block, and a spring piece is engaged between the locking block and the inner wall of the groove.

[0009] The present invention further illustrates that the outer surface of the trapezoidal block is provided with an inclined groove, a connecting groove and a reset groove, and the inclined groove, the connecting groove and the reset groove are interconnected. The ball is rotatably connected in the inclined groove, the connecting groove and the reset groove, and the connecting groove is vertical.

[0010] The present invention further illustrates that the inner wall of the support rod is provided with a sliding groove and a spiral groove, and the sliding groove and the spiral groove are interconnected. A ball is embedded in the outer end of the hydraulic rod, and the ball is rolled and connected in the sliding groove and the spiral groove. When the ball enters the reset groove, the ball enters the spiral groove. An insert is integrally formed on the inner wall of the collar, and the ball is rolled and connected in the insert. Both are magnetic, and their magnetic poles are opposite.

[0011] The present invention further illustrates that after the spring is deformed, its outer surface comes into contact with the inner wall of the collar.

[0012] The present invention further describes that the detection method includes the following steps: Step S1, testing the initial electrical parameters of the anode foil and cathode foil samples respectively; Step S2, placing the anode foil and cathode foil samples respectively in a reflux device containing electrolyte, and... A reflux cooking test was conducted, with a test duration of [duration missing]. Step S3: After the test, observe the surface characteristics of the sample and test its electrical performance parameters after immersion. If the surface characteristics of either the anode foil or the cathode foil do not meet the standard, the hydration resistance is directly judged to be unqualified. Calculate the rate of change of the electrical performance parameters. When any rate of change exceeds the preset failure threshold, the hydration resistance of the material combination is judged to be unqualified, otherwise it is qualified.

[0013] The present invention further explains that the electrical performance parameters in step S3 include withstand voltage, boost time, specific capacitance, and leakage current. Based on the initial electrical performance parameters and the electrical performance parameters obtained after cooking, the withstand voltage reduction rate, boost time increase rate, specific capacitance reduction rate, and leakage current increase rate are calculated respectively. Indicates the initial aluminum foil withstand voltage value, in Indicates the initial aluminum foil boost time value, in Indicates the initial specific volume of aluminum foil, in Indicates the initial aluminum foil leakage current; Indicates the pressure resistance value of aluminum foil after boiling, in... This indicates the time it takes for the aluminum foil to pressurize after boiling. Indicates the specific volume of aluminum foil after boiling, in This indicates the leakage current of the aluminum foil after boiling.

[0014] The present invention further explains that the preset failure threshold is based on The reflux cooking test results were set; specifically: pressure resistance value. Decay to initial value 90% and below, boost time Increase to the initial value 500% or more of the leakage current Increase to the initial value 200% or more, or specific volume Decay to initial value 95% or less; when the anode foil exhibits at least one of the following conditions: , , , Or the cathode foil may produce at least one of the following conditions: , , If the anode foil, cathode foil, and electrolyte are used, the corresponding aluminum electrolytic capacitor is deemed to have unqualified hydration resistance; if the anode foil meets the requirements... , , , And the cathode foil satisfies , , In this case, the corresponding aluminum electrolytic capacitor composed of such anode foil, cathode foil, and electrolyte is deemed to have qualified water resistance.

[0015] The present invention further explains that, in step S3, when the positive foil sample exhibits slow voltage increase and cannot quickly measure the withstand voltage value after the test, the voltage is increased to... If the withstand voltage value is not measured at that time, it is directly judged as a failure, while the leakage current is not used as an evaluation criterion for the negative foil.

[0016] The present invention further explains that the sample size in step S1 is... Furthermore, at least three samples of each type are tested; significant deterioration of the surface features includes the observation of black corrosion spots or other obvious corrosion marks.

[0017] Compared with the prior art, the beneficial effects achieved by the present invention are: Significantly shortening the testing time and accurately simulating real failure mechanisms, the system utilizes a combination of micro-positive pressure, forced convection, and gradient heating, along with a continuous liquid water film formed by a serpentine condenser tube, to forcibly accelerate the hydration and degradation reaction of the aluminum oxide film. This allows for the simulation of the hydration failure process of capacitors during long-term use in a short time. The complete liquid water film can fully encapsulate the capacitor casing, seals, leads, and other parts, eliminating hydrophobic dead zones and the problem of drying out and losing moisture. This allows water molecules to quickly wet the gaps in the plastic seal and the micropores of the oxide film, closely conforming to the laws of real aging and failure. While reducing the testing time, the testing and judgment standards are not changed, ensuring the accuracy of the test results. To optimize the stability of the device operation and improve the safety and success rate of testing, the device utilizes hydraulic drive, trapezoidal channels, and spring-loaded reset structure to achieve alternating clockwise and counterclockwise shaking and intermittent lifting of the double-necked flask. This efficiently shakes off condensed droplets, ensuring continuous and complete water film coverage. Combined with a sliding groove, spiral groove, and magnetic ball bearing structure, the shaking and reset amplitude are precisely controlled, preventing flask breakage and seal failure, as well as preventing uneven condensate dripping that could lead to sample test failure. At the same time, the deformation amplitude of the spring is limited to prevent the device from jamming, ensuring a stable, smooth, safe, and reliable testing process. The testing is fast, employing high-temperature reflux boiling to accelerate the simulation of hydration degradation. It eliminates the need for assembling finished capacitors, with test duration controlled within 48 hours and rapid judgment requiring only 6 hours—far faster than traditional methods such as high-temperature sealing and impregnation, significantly improving the efficiency of material screening and formulation verification. The judgment criteria are quantified and standardized, using changes in withstand voltage, voltage rise time, leakage current, and specific capacitance as quantifiable judgment values, combined with surface appearance for rapid preliminary judgment. The test results exhibit strong repeatability and comparability. It is highly applicable and easy to operate, requiring only a conventional oil bath and reflux device. It requires small sample volumes and no complex components, making it suitable for rapid selection and quality control of key materials such as low-voltage anode foil, cathode foil, and electrolytes. Attached Figure Description

[0018] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a flowchart of a rapid testing method for the hydration resistance of low-voltage aluminum electrolytic capacitors according to the present invention; Figure 2 This is a schematic diagram of the reflux device of the present invention; Figure 3 This is a schematic diagram of the internal structure of the support rod and tray of the present invention; Figure 4 This is a plan view of the internal structure of the support rod and tray of the present invention; Figure 5 This is a plan view of the internal structure of the collar of the present invention; Figure 6 This is an exploded view of the internal structure of the tray of the present invention; Figure 7 This is a schematic diagram of the limiting block structure of the present invention; In the diagram: 1. Base; 2. Oil bath; 3. Double-necked flask; 4. Serpentine condenser; 41. Limiting block; 42. Trapezoidal block; 421. Inclined groove; 422. Connecting groove; 423. Reset groove; 43. Spring; 5. Support rod; 51. Hydraulic rod; 511. Ball; 52. Collar; 521. Ball bearing; 522. Insert; 53. Slide groove; 54. Spiral groove; 6. Screw block; 7. Support rod; 8. Tray; 81. Locking block. Detailed Implementation

[0019] The following detailed, non-limiting description of the technical solution of the present invention, in conjunction with preferred embodiments and accompanying drawings, is provided. Obviously, the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0020] Please see Figures 1-7 The present invention provides a technical solution: a rapid detection device and method for the water resistance of low-voltage aluminum electrolytic capacitors, including a reflux device, which includes a base 1, an oil bath 2, a double-necked flask 3 and a serpentine condenser 4, and a support rod 5 fixedly installed above the base 1. The outer side of the support rod 5 is threaded with a screw block 6. A support rod 7 is integrally formed on one side of the screw block 6. A tray 8 is integrally formed at one end of the support rod 7. The serpentine condenser tube 4 is connected above the double-necked flask 3. A limiting block 41 is integrally formed on the outer side of the upper end. The limiting block 41 is in contact with the upper surface of the tray 8 and is used to limit the serpentine condenser tube 4. The upper and lower ends of the serpentine condenser tube 4 are respectively provided with a water inlet and a water outlet, and the cooling liquid is circulated through the water inlet and the water outlet. The oil bath 2 is placed above the base 1, and the double-necked flask 3 is placed inside the oil bath 2. The outer side of the limiting block 41 is integrally formed with a trapezoidal block 42, the support rod 5 is through-shaped, and the inner wall is slidably connected with a hydraulic rod 51. The outer end of the hydraulic rod 51 is integrally formed with a collar 52, and the inner wall of the collar 52 is slidably connected with a ball 521. The ball 521 contacts the outer surface of the trapezoidal block 42, and the left end of the support rod 5 is connected to an external hydraulic pump pipeline. Deionized water is added to the double-necked flask 3, and the capacitor to be tested is placed inside the double-necked flask 3 to form a completely sealed space. Then, the serpentine condenser 4 is inserted into the tray 8 through the limiting block 41 to support the double-necked flask 3. At the same time, the position and height of the screw block 6 are adjusted by the threaded transmission to adjust the position and height of the double-necked flask 3. After the adjustment is completed, the oil bath 2 is heated, and the bottom of the double-necked flask 3 is heated to generate saturated steam. At the same time, the serpentine condenser 4 circulates and cools, causing the top of the double-necked flask 3 to condense and form a continuous condensation water film. Then, through micro-positive pressure, forced convection, and gradient heating, the hydration and degradation reaction between the aluminum oxide film and water molecules is forcibly accelerated, simulating the hydration failure process of the capacitor during long-term use in a short time, so as to achieve rapid detection. During the testing process, the external hydraulic pump operates, creating negative pressure inside the support rod 5. This causes the hydraulic rod 51 to slide, which in turn moves the ball bearing 521, causing it to roll on the surface of the trapezoidal block 42 and exert pressure on it. This pressure causes the trapezoidal block 42 to rotate, which in turn rotates the double-necked flask 3, causing the condensed droplets at its top to fall off. This ensures that the water film completely coats the capacitor casing, seal, leads, and alumina oxide film, preventing surface drying and moisture loss. The hydration degradation process is continuous and uninterrupted, directly reducing the detection time and accelerating the penetration of water molecules into micropores. The complete liquid water film replaces scattered water vapor, making it easier for water molecules to wet the gaps in the plastic seal, the sealing adhesive layer, and the micropores of the aluminum foil oxide film. This accelerates the interlayer penetration and hydration corrosion process, closely matching the actual long-term aging and failure mechanism. Combined with the condensation dripping and steam fumigation structure, a stable thick water film is continuously attached to the capacitor surface, effectively increasing the amount of condensation, extending the moisturizing time, and amplifying the acceleration effects of temperature, micro-positive pressure, and convection.

[0021] The outer surface of the limiting block 41 is provided with a groove, and the upper surface of the tray 8 is integrally formed with a locking block 81. A spring piece 43 is engaged between the locking block 81 and the inner wall of the groove.

[0022] The outer surface of the trapezoidal block 42 is provided with an inclined groove 421, a connecting groove 422 and a reset groove 423, and the inclined groove 421, the connecting groove 422 and the reset groove 423 are interconnected. The ball 521 is rotatably connected in the inclined groove 421, the connecting groove 422 and the reset groove 423, and the connecting groove 422 is vertical. When the ball bearing 521 presses against the inclined surface of the trapezoidal block 42, it rolls in the inclined groove 421 and generates an axial force to push the trapezoidal block 42 upward. This force drives the double-necked flask 3 upward through the serpentine condenser tube 4. When the ball bearing 521 rolls to the position of the connecting groove 422, it is subjected to the weight of the double-necked flask 3 and the serpentine condenser tube 4, causing the ball bearing 521 to move relative to the connecting groove 422. The double-necked flask 3 and the serpentine condenser tube 4 fall rapidly, causing them to shake. This shakes the condensed droplets at the top of the double-necked flask 3, causing them to fall off, further accelerating the dripping speed of the droplets, thereby further accelerating the interlayer penetration and hydration corrosion process. Simultaneously, when the limiting block 41 rotates, the spring piece 43 deforms under force and generates a reaction force. When the ball 521 reaches the upper end of the connecting groove 422, the reaction force of the spring piece 43 pushes the limiting block 41 to reset quickly. The ball 521 rolls along the reset groove 423, thereby causing the double-necked flask 3 to rotate alternately in both directions, strengthening the shaking intensity of the double-necked flask 3, further enhancing the speed of dripping, ensuring the integrity of the water film on the capacitor surface. The low surface tension dielectric combined with the complete water film makes it easier to spread and wet the shell and lead corners, eliminating hydrophobic dead corners, further improving the hydration reaction rate, and achieving speed increase without changing the judgment criteria.

[0023] The inner wall of the support rod 5 is provided with a sliding groove 53 and a spiral groove 54, and the sliding groove 53 and the spiral groove 54 are connected to each other. The outer end of the hydraulic rod 51 is embedded with a ball 511, and the ball 511 is rolled in the sliding groove 53 and the spiral groove 54. When the ball 521 enters the reset groove 423, the ball 511 enters the spiral groove 54. The inner wall of the collar 52 is integrally formed with an insert 522. The ball 521 is rolled and connected to the insert 522. Both of them are magnetic and have opposite magnetic poles. Meanwhile, when the ball 521 enters the reset groove 423, the ball 511 slides into the spiral groove 54 through the slide groove 53 and generates axial force, causing the hydraulic rod 51 to rotate slightly. This causes the insert 522 to rotate slightly through the collar 52, and the ball 521 to rotate slightly. This increases the squeezing force between the ball 521 and the inner wall of the reset groove 423, and increases the friction. This relatively slows down the reset speed of the double-necked flask 3, relatively reduces the shaking intensity, and avoids the double-necked flask 3 from cracking or failing to seal due to large shaking. It also prevents the steam return path from becoming disordered, causing the condensate droplet point to deviate and the sample to be watered unevenly. This also prevents the capacitor from being severely hydrated, so that some parts are not watered, which would lead to the test being scrapped. This improves the safety and stability of the test. The magnetic attraction of the insert 522 to the ball 521 ensures that the ball 521 is always embedded in the insert 522, preventing it from falling out.

[0024] After the spring 43 is deformed, its outer surface comes into contact with the inner wall of the collar 52; When the collar 52 moves, the spring piece 43 is compressed and deformed. Its outer surface comes into contact with and is compressed against the inner wall of the collar 52. The collar 52 limits the deformation of the spring piece 43, thereby further reducing the strength during reset, improving the protection strength, and limiting the collar 52 to avoid excessive rotation of the hydraulic rod 51, which would cause excessive friction between the ball 521 and the reset groove 423, preventing jamming and improving the smoothness of the operation. Example 1:

[0025] For model number , The target lifespan is , Rapid testing of the hydration resistance of low-voltage aluminum electrolytic capacitors is performed, as follows: Figure 1 As shown, the reflux device used is as follows Figure 2 As shown (consisting of an oil bath 2, a double-necked flask 3, and a serpentine condenser 4), it does not need to be assembled into a finished capacitor. The specific steps are as follows: Step S1: Take the anode foil used for this type of capacitor ( ) and cathode foil ( Cut to size For each type of test sample, three pieces were taken, and their initial electrical parameters were tested. These electrical parameters included specific capacitance, withstand voltage, and leakage current. This indicates the initial aluminum foil leakage current. This indicates the initial specific volume of the aluminum foil. This indicates the initial aluminum foil withstand voltage value. After the test, the anode foil and cathode foil test samples were rinsed with deionized water, air-dried, and ready for use. Step S2: Prepare two identical double-necked flasks 3 as containers, and add [the following ingredients] to each flask. This type of capacitor uses a special electrolyte A, which has a water content of [missing information]. The main solvent is ethylene glycol + water, and the conductivity is [missing value]. , After assembling the reflux device, completely immerse the anode foil test sample and the cathode foil test sample in the electrolyte A of the two double-necked flasks 3, and set the temperature of the oil bath 2 to [temperature value missing]. A reflux cooking test was conducted, and the test duration was... ; Step S3: After the test, stop heating and wait for the system to cool to room temperature. Take out the anode foil and cathode foil test samples, wash the residual electrolyte on the aluminum foil surface with deionized water, and let it air dry naturally. Observe the surface characteristics of the samples: the surface of the anode foil test sample is normal, with no black corrosion spots or other corrosion marks; the surface of the cathode foil test sample has black corrosion spots, and the surface characteristics are obviously deteriorated. Step S4: Perform electrical parameter testing on the above samples after impregnation, in order to... This indicates the pressure resistance value of the aluminum foil after boiling. This indicates the time it takes for the aluminum foil to pressurize after boiling. This indicates the leakage current of the aluminum foil after boiling. This indicates the specific volume of the aluminum foil after boiling; tests were conducted on the anode foil. Cathode foil: ; Based on the preset failure threshold, the cathode foil exhibits [failure]. There are two possibilities, therefore it is directly determined that the structure is constructed using electrolyte A, anode foil, and cathode foil. , The low-voltage aluminum electrolytic capacitors failed to meet the hydration resistance requirements and were prone to hydration failure within the target lifespan.

[0026] Compare with Example 1: The traditional high-temperature sealing and impregnation method was used for model number , The target lifespan is , The hydration resistance of the low-voltage aluminum electrolytic capacitor was tested. The anode foil, cathode foil, and electrolyte A used were exactly the same as in Example 1. The specific method is as follows: Step S1: After cutting the anode foil and cathode foil used for this type of capacitor, stack and wind them in the order of anode foil-electrolytic paper-cathode foil-electrolytic paper to form a capacitor core package. After immersing the core package in electrolyte A, assemble it into an aluminum shell to produce the capacitor. , Low-voltage aluminum electrolytic capacitors, applying voltage to the capacitors aging Then, 50 capacitors were randomly selected and numbered, and their average leakage current was tested. The average capacity is 98% of the nominal value, and the average loss is 5%. Step S2: Place the above 50 capacitors in In the oven, High-temperature durability life test; after the test, the capacitors were removed and allowed to return to room temperature before their electrical parameters were tested. Compared with the initial test data, the average leakage current of this batch of capacitors increased by 312%, the average capacitance decay rate was 30.8%, and the average loss increased by 235%. Step S3: Disassemble the capacitors after the high-temperature durability life test and observe the surface characteristics of the aluminum foil: There are no obvious abnormalities on the surface of the anode foil. Large areas of black corrosion spots and corrosion streaks appear on the surface of the cathode foil of 45 out of 50 capacitors, indicating that the cathode foil has undergone a severe hydration reaction, which leads to a sharp increase in capacitor leakage current and a significant decrease in capacitance. The capacitor failure rate reaches 90%. The test results of Comparative Example 1 are highly consistent with the detection results of Example 1 of the present invention, proving that the method of the present invention can accurately predict the risk of hydration failure of low-voltage aluminum electrolytic capacitors, and the detection cycle is shortened from... Significantly shortened to This greatly improves detection efficiency. Example 2:

[0027] For model number , The target lifespan is , Rapid testing of the hydration resistance of low-voltage aluminum electrolytic capacitors is performed, as follows: Figure 1 As shown, the reflux device consists of an oil bath 2, a double-necked flask 3, and a serpentine condenser 4. It does not require assembly into a finished capacitor and specifically includes the following steps: Step S1: Take the anode foil used for this type of capacitor ( ) and cathode foil ( 2) Cut to size For each type of test sample, three pieces were taken, and their initial electrical parameters were tested separately. This indicates the initial aluminum foil leakage current. This indicates the initial specific volume of the aluminum foil. This indicates the initial aluminum foil pressure resistance value; after testing, the sample should be rinsed with deionized water and allowed to air dry for later use. Step S2: Prepare two double-necked flasks 3, and add to each flask... This type of capacitor uses a special electrolyte B, which has a water content of [missing information]. The main solvent is ethylene glycol, and the conductivity is [missing information]. The anode and cathode foil test samples were completely immersed in electrolyte B, and the reflux device was assembled. The temperature of the oil bath 2 was set to [temperature value missing]. A reflux cooking test was conducted, and the test duration was... ; Step S3: After the test, cool to room temperature, take out the sample, clean and dry it, and observe the surface characteristics: There are no black corrosion spots or other corrosion traces on the surface of the anode foil and cathode foil test samples, and the surface characteristics are not obviously deteriorated. Step S4: Perform electrical parameter testing on the sample after impregnation, in order to... These represent the pressure rise time, withstand voltage, leakage current, and specific capacitance after cooking, respectively; The anode foil was tested and found to be: Cathode foil: ; Based on the preset failure threshold, the anode foil meets the following criteria: The cathode foil satisfies the following conditions. The conditions are met. Therefore, it is determined that the electrolyte B, anode foil, and cathode foil are used to construct... The low-voltage aluminum electrolytic capacitor has qualified resistance to hydration and is not prone to hydration failure within the target lifespan.

[0028] Compare with Example 2: The traditional high-temperature sealing and impregnation method was used for model number The target lifespan is , The low-voltage aluminum electrolytic capacitor was tested for its resistance to hydration. The anode foil, cathode foil, and electrolyte B used were exactly the same as in Example 2. The specific method is as follows: Step S1: The anode foil, cathode foil, and electrolytic paper of this type of capacitor are wound into a core package, impregnated with electrolyte B, and then assembled. Low-voltage aluminum electrolytic capacitors, with applied voltage aging Then, 50 capacitors were randomly selected, and their average leakage current was tested. The average capacity is 101% of the nominal value, and the average loss is 2%. Step S2: Place the above 50 capacitors in In the oven, High-temperature durability life test; after the test, the capacitors were cooled to room temperature and their electrical parameters were tested. Compared with the initial data, the average leakage current of this batch of capacitors increased by 90%, the average capacitance decay rate was 3%, and the average loss increased by 10%. Step S3: Disassemble the capacitors after the test and observe the aluminum foil surface: there are no black corrosion spots or corrosion marks on the surface of the anode foil and cathode foil, and no obvious hydration reaction characteristics. All 50 capacitors can work normally, and the failure rate is 0. The test results of Comparative Example 2 are completely consistent with the test results of Example 2 of the present invention, proving that the method of the present invention can accurately determine the water resistance qualification of low voltage aluminum electrolytic capacitors while conducting rapid testing, providing a reliable basis for raw material matching. Example 3:

[0029] For model number The target lifespan is Rapid testing of the hydration resistance of aluminum electrolytic capacitors is performed, as follows: Figure 1 As shown, the reflux device consists of an oil bath 2, a double-necked flask 3, and a serpentine condenser 4. It does not require assembly into a finished capacitor and specifically includes the following steps: Step S1: Take the anode foil used for this type of capacitor ( ) and cathode foil ( Cut to size For each type of test sample, three pieces were taken, and their initial electrical parameters were tested separately. This indicates the initial aluminum foil leakage current. This indicates the initial specific volume of the aluminum foil. This indicates the initial aluminum foil pressure resistance value; after testing, the sample should be cleaned and air-dried for later use. Step S2: Prepare two double-necked flasks 3, and add to each flask... This type of capacitor uses a special electrolyte C, and electrolyte C has a water content of [missing information]. The main solvent is ethylene glycol + water, and the conductivity is [missing value]. , The anode and cathode foil test samples were completely immersed in electrolyte C, and a reflux device was assembled. The temperature of the oil bath 2 was set to [temperature value missing]. A reflux cooking test was conducted, and the test duration was... ; Step S3: After the test, cool to room temperature, take out the sample, clean and dry it, and observe the surface characteristics: There are no black corrosion spots or other corrosion traces on the surface of the anode foil and cathode foil test samples, and the surface characteristics are not obviously deteriorated. Step S4: After impregnation, the electrical parameters of the sample were tested. During the test, it was found that the voltage rise of the anode foil was slow. (The withstand voltage value still cannot be measured), according to the method of the present invention, the electrolyte C, anode foil, and cathode foil are used to determine the... Aluminum electrolytic capacitors fail to meet hydration resistance standards and are prone to hydration failure within their target lifespan.

[0030] Compare with Example 3: The traditional high-temperature sealing and impregnation method was used for model number The target lifespan is The aluminum electrolytic capacitor was tested for its resistance to hydration. The anode foil, cathode foil, and electrolyte C used were exactly the same as in Example 3. The specific method is as follows: Step S1: The anode foil, cathode foil, and electrolytic paper of this type of capacitor are wound into a core package, impregnated with electrolyte C, and then assembled. Aluminum electrolytic capacitor, voltage applied aging Then, 50 capacitors were randomly selected, and their average leakage current was tested. The average capacity is 98% of the nominal value, and the average loss is 5%. Step S2: Place the above 50 capacitors in In the oven, High-temperature durability life test; after the test, the capacitors were cooled to room temperature and their electrical parameters were tested. Compared with the initial data, the average leakage current of this batch of capacitors increased by 290%, the average capacitance decay rate was 33%, and the average loss increased by 110%. Step S3: Dissect the capacitors after the test and observe the aluminum foil surface: There are no obvious abnormalities on the cathode foil surface. Fine black corrosion spots appear on the anode foil surface of 39 out of 50 capacitors, and the oxide film is partially damaged. This indicates that the anode foil has undergone a hydration reaction, which leads to a decrease in the capacitor's withstand voltage and an increase in leakage current. The capacitor failure rate reaches 78%. The test results of Comparative Example 3 are highly consistent with the detection results of Example 3 of the present invention, proving that the method of the present invention can effectively deal with special situations in the detection process (such as slow pressure rise), achieve accurate detection by replacing the judgment criteria, and at the same time shorten the detection cycle from shortened to This significantly reduces testing time and material costs.

[0031] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0032] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features, and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A rapid detection device for the hydration resistance of low-voltage aluminum electrolytic capacitors, comprising a reflux device, characterized in that: The reflux device includes a base (1), an oil bath (2), a double-necked flask (3), and a serpentine condenser (4). A support rod (5) is fixedly installed above the base (1). The outer side of the support rod (5) is threaded with a screw block (6), and a support rod (7) is integrally formed on one side of the screw block (6). A tray (8) is integrally formed at one end of the support rod (7). The serpentine condenser (4) is connected above the double-necked flask (3), and a limiting block (41) is integrally formed on the outer side of the upper end. The limiting block (41) is in contact with the upper surface of the tray (8) and is used to limit the serpentine condenser (4). The upper and lower ends of the serpentine condenser (4) are respectively provided with a water inlet and a water outlet, and the liquid is circulated and cooled through the water inlet and the water outlet. The oil bath (2) is placed above the base (1), and the double-necked flask (3) is built into the oil bath (2). The outer side of the limiting block (41) is integrally formed with a trapezoidal block (42), the support rod (5) is through-shaped and the inner wall is slidably connected with a hydraulic rod (51), the outer end of the hydraulic rod (51) is integrally formed with a collar (52), and the inner wall of the collar (52) is slidably connected with a ball (521), the ball (521) is in contact with the outer surface of the trapezoidal block (42), and the left end of the support rod (5) is connected to an external hydraulic pump pipeline.

2. The device for rapid detection of hydration resistance of low-voltage aluminum electrolytic capacitors according to claim 1, characterized in that: The outer surface of the limiting block (41) is provided with a groove, and the upper surface of the tray (8) is integrally formed with a locking block (81), and a spring piece (43) is engaged between the locking block (81) and the inner wall of the groove.

3. The device for rapid detection of hydration resistance of low-voltage aluminum electrolytic capacitors according to claim 2, characterized in that: The outer surface of the trapezoidal block (42) is provided with a sloping groove (421), a connecting groove (422) and a reset groove (423), and the sloping groove (421), the connecting groove (422) and the reset groove (423) are interconnected. The ball (521) is rotatably connected in the sloping groove (421), the connecting groove (422) and the reset groove (423), and the connecting groove (422) is vertical.

4. The device for rapid detection of hydration resistance of low-voltage aluminum electrolytic capacitors according to claim 3, characterized in that: The inner wall of the support rod (5) is provided with a sliding groove (53) and a spiral groove (54), and the sliding groove (53) and the spiral groove (54) are connected to each other. The outer end of the hydraulic rod (51) is embedded with a ball (511), and the ball (511) is rolled in the sliding groove (53) and the spiral groove (54). When the ball (521) enters the reset groove (423), the ball (511) enters the spiral groove (54). The inner wall of the collar (52) is integrally formed with an insert (522). The ball (521) is rolled and connected to the insert (522), and both are magnetic with opposite magnetic poles.

5. The rapid detection device for the hydration resistance of low-voltage aluminum electrolytic capacitors according to claim 4, characterized in that: After the spring (43) is deformed, its outer surface comes into contact with the inner wall of the collar (52).

6. A rapid testing method for the hydration resistance of low-voltage aluminum electrolytic capacitors, as described in claim 1, characterized in that: The detection method includes the following steps: Step S1: Test the initial electrical parameters of the anode foil and cathode foil samples respectively; Step S2: Place the anode foil and cathode foil samples into a reflux reflux device containing electrolyte, respectively. A reflux cooking test was conducted, with a test duration of [duration missing]. ; Step S3: After the test, observe the surface characteristics of the sample and test its electrical performance parameters after immersion. If either the anode foil or the cathode foil does not meet the standard, the hydration resistance is directly judged to be unqualified. Calculate the rate of change of the electrical performance parameters. If any rate of change exceeds the preset failure threshold, the hydration resistance of the material combination is judged to be unqualified; otherwise, it is qualified.

7. The detection method of the rapid detection device for the hydration resistance of low-voltage aluminum electrolytic capacitors according to claim 6, characterized in that: The electrical performance parameters in step S3 include withstand voltage, boost time, specific capacitance, and leakage current. Based on the initial electrical performance parameters and the electrical performance parameters obtained after cooking, the rate of decrease in withstand voltage, the rate of increase in boost time, the rate of decrease in specific capacitance, and the rate of increase in leakage current are calculated respectively. Indicates the initial aluminum foil withstand voltage value, in Indicates the initial aluminum foil boost time value, in Indicates the initial specific volume of aluminum foil, in Indicates the initial aluminum foil leakage current; by Indicates the pressure resistance value of aluminum foil after boiling, in... This indicates the time it takes for the aluminum foil to pressurize after boiling. Indicates the specific volume of aluminum foil after boiling, in This indicates the leakage current of the aluminum foil after boiling.

8. The detection method of the rapid detection device for the hydration resistance of low-voltage aluminum electrolytic capacitors according to claim 7, characterized in that: The preset failure threshold is based on The results of the reflux cooking test were set; Specifically: withstand voltage value Decay to initial value 90% and below, boost time Increase to the initial value 500% or more of the leakage current Increase to the initial value 200% or more, or specific volume Decay to initial value 95% and below; When the anode foil exhibits at least one of the following conditions: , , , Or the cathode foil may produce at least one of the following conditions: , , If the aluminum electrolytic capacitor composed of this type of anode foil, cathode foil, and electrolyte is found to have unqualified hydration resistance, then it is determined that the hydration resistance is unqualified. When the anode foil satisfies , , , And the cathode foil satisfies , , In this case, the corresponding aluminum electrolytic capacitor composed of such anode foil, cathode foil, and electrolyte is deemed to have qualified water resistance.

9. The detection method of the rapid detection device for the hydration resistance of low-voltage aluminum electrolytic capacitors according to claim 8, characterized in that: In step S3, when the positive foil sample exhibits slow voltage increase and the withstand voltage value cannot be quickly measured after the test, the voltage is increased to... If the withstand voltage value is not measured at that time, it is directly judged as a failure, while the leakage current is not used as an evaluation criterion for the negative foil.

10. The detection method of the rapid detection device for the hydration resistance of low-voltage aluminum electrolytic capacitors according to claim 9, characterized in that: The sample size in step S1 is: And the number of tests for each sample must be at least 3 pieces; Significant deterioration of surface features includes the observation of black corrosion spots or other obvious signs of corrosion.

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