Method for detecting corrosion resistance of rubber plug

Abstract

The invention discloses a method for detecting the corrosion resistance of a rubber plug. The method comprises the following steps: 1) soaking the rubber plug in an electrolyte for 3-10 hours; (2) taking the electrolyte in the step (1); taking an anode guide pin and a cathode guide pin, and immersing aluminum tongues of the anode guide pin and the cathode guide pin into the electrolyte; 3) connecting the anode guide pin with a power supply anode, and connecting the cathode guide pin with a power supply cathode; applying a direct-current voltage matched with the highest withstand voltage of the electrolyte; the time lasts for 20-60 minutes; (4) wiping the electrolyte on the surface of the anode guide pin, and checking whether the positions of an aluminum tongue and an aluminum stem of the anode guide pin are corroded and blackened or not by using a magnifying lens or a microscope; and if yes, determining that the product is unqualified. According to the method for detecting the corrosion resistance of the rubber plug, the time is greatly shortened; the traditional method needs more than 1000 hours of high-temperature durability / load test, while the scheme can be completed in only one day, so that the efficiency is improved by hundreds of times.

Description

TECHNICAL FIELD

[0001] The application relates to a detection method of an aluminum electrolytic capacitor rubber plug, in particular to a detection method of corrosion resistance of the rubber plug. BACKGROUND

[0002] Aluminum electrolytic capacitors are indispensable key components in electronic devices, widely used in power supply, consumer electronics, industrial control and new energy vehicles. Its core performance (such as capacity stability, equivalent series resistance (ESR), leakage current and service life) not only depends on the performance of anode foil and electrolyte, but also is closely related to the chemical compatibility of rubber plug. Rubber plug is usually made of butyl rubber (IIR) or ethylene propylene diene rubber (EPDM), which mainly seals the internal electrolyte of the capacitor to prevent leakage and provides certain explosion-proof function. However, the electrolyte is usually composed of strong polar solvents (such as gamma-butyrolactone, ethylene glycol), ammonium carboxylate salt and additives, which have high chemical activity. Under the long-term high temperature and high pressure working environment, the electrolyte may penetrate the rubber plug, causing its swelling, hardening or molecular chain degradation, and then causing sealing failure, electrolyte evaporation or capacitor explosion and other serious problems.

[0003] At present, the mainstream certification method of the industry for the compatibility of rubber plug and electrolyte is to make it into a complete aluminum electrolytic capacitor sample, and then carry out long-time high-temperature load / durability test. However, this method has the following significant defects: Long test period: traditional high-temperature load / durability test usually needs hundreds to thousands of hours, which cannot meet the rapid research and development and mass production demand, and seriously delays the product listing time.

[0004] High certification cost: complete capacitor samples need to be prepared for each test, which has high material and manufacturing cost.

[0005] Many interference factors: the test results are affected by many factors such as aluminum foil corrosion, electrolytic paper aging, packaging process, etc., and it is difficult to evaluate the failure mechanism of the rubber plug alone.

[0006] Lack of early screening means: in the material development stage, if the adaptability of the rubber plug and the electrolyte cannot be quickly judged, a large number of invalid formulas may enter the later test, causing waste of resources.

[0007] The existing technology mainly evaluates the electrolyte resistance of the rubber plug through simple immersion experiment, but these methods cannot simulate the actual electrochemical corrosion environment, and lack of correlation verification with capacitor performance. Therefore, a rapid and accurate rubber plug certification method is urgently needed, which can predict its long-term compatibility in a short time, thereby greatly shortening the research and development cycle and reducing the trial and error cost. SUMMARY

[0008] The technical problem solved by the present application is to overcome the shortcomings of the prior art and provide a rubber plug corrosion resistance detection method.

[0009] To solve the above technical problems, the technical solution of the present application is as follows: a rubber plug corrosion resistance detection method, comprising the following steps: 1) immerse the rubber plug in the electrolyte for 3-10 hours; 2) take the electrolyte completed in step 1); place it in a detection container; take the anode guide needle and the cathode guide needle, so that the aluminum tongue of the anode guide needle and the cathode guide needle is immersed in the electrolyte; 3) connect the anode guide needle to the positive electrode of the power supply, and connect the cathode guide needle to the negative electrode of the power supply; apply a direct current voltage matching the highest voltage resistance of the electrolyte; continue for 20-60 minutes; the temperature is 105℃~130℃; 4) wipe the electrolyte on the surface of the anode guide needle, and use a magnifying glass or a microscope to check whether there is corrosion and blackening phenomenon at the position of the aluminum tongue and the aluminum stem of the anode guide needle; if there is, it is unqualified.

[0010] The rubber plug corrosion resistance detection method described above, preferably, in step 1), the weight of the rubber plug is 10%-40% of the weight of the electrolyte.

[0011] The rubber plug corrosion resistance detection method described above, preferably, in step 3), the anode guide needle and the cathode guide needle are fixed through the same rubber plug in step 1).

[0012] The rubber plug corrosion resistance detection method described above, preferably, in step 3), the aluminum stem of the anode guide needle and the cathode guide needle is fixed in the lead hole of the rubber plug.

[0013] The rubber plug corrosion resistance detection method described above, preferably, in step 1), the rubber plug immersed in the electrolyte is cut into granular shape.

[0014] Compared with the prior art, the rubber plug corrosion resistance detection method of the present application has the advantages that: the rubber plug corrosion resistance detection method of the present application greatly shortens the time; the traditional method needs 1000 hours or more high temperature durability / load test, while the present scheme can be completed in one day, and the efficiency is improved by hundreds of times. At the same time, the detection method of the present application does not need to prepare complete capacitors, only needs rubber plug, electrolyte and simple test device, saves a lot of material and manufacturing cost. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 For the structure diagram of the electrochemical corrosion test in the rubber plug corrosion resistance detection method of Example 1. DETAILED DESCRIPTION

[0016] For the purpose of facilitating the understanding of the present application, the present application will be described in more detail below with reference to the accompanying drawings and preferred embodiments, but the scope of protection of the present application is not limited to the following specific embodiments.

[0017] It should be particularly noted that when an element is described as being "fixed to, attached to, connected to or communicated with" another element, it can be directly fixed, attached, connected or communicated with the other element, or indirectly fixed, attached, connected or communicated with the other element through other intermediate connecting elements.

[0018] Unless otherwise defined, all the professional terms used below have the same meaning as commonly understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present application. Embodiment 1

[0019] A detection method for the corrosion resistance of a rubber plug, comprising the following steps: 1) Soak the rubber plug in an electrolyte for 3-10 hours; the weight of the rubber plug is 10%-40% of the weight of the electrolyte. In this embodiment, the rubber plug used for soaking is cut into granules, which can accelerate the swelling speed of the rubber plug. In this embodiment, the temperature during the soaking of the rubber plug is 85℃-130℃, and high temperature can accelerate the penetration of the electrolyte, simulating the swelling effect under long-term use.

[0020] 2) Take the electrolyte completed in step 1); place it in a detection container; take the anode guide needle and the cathode guide needle, so that the aluminum tongues of the anode guide needle and the cathode guide needle are immersed in the electrolyte. The detection container can be a beaker or a large aluminum shell.

[0021] 3) As shown in Figure 1 , the anode guide needle is connected to the positive pole of the power supply, and the cathode guide needle is connected to the negative pole of the power supply; a direct current voltage matching the highest voltage resistance of the electrolyte is applied; the duration is 20-60 minutes; the temperature is 105℃~130℃, and the corrosion effect of the electrolyte on the aluminum stems and / or aluminum tongues is forced to accelerate. In this embodiment, the anode guide needle and the cathode guide needle in step 3) are fixed by the same rubber plug in step 1); the aluminum stems of the anode guide needle and the cathode guide needle are fixed in the lead hole of the rubber plug.

[0022] In this embodiment, the anode guide needle and the cathode guide needle are fixed by the rubber plug, which can reduce the state of the aluminum electrolytic capacitor as much as possible during use.

[0023] The detection method of this embodiment directly simulates the actual working condition by electrochemical accelerated corrosion, which is closer to the real failure mode than the pure soaking experiment.

[0024] 4) Wipe the surface of the anode needle with electrolyte, check the position of the anode needle aluminum tongue and aluminum stem with a magnifying glass or microscope for corrosion and blackening. If there is, it is unqualified.

[0025] In this embodiment, after the rubber plug is soaked in the electrolyte in step 1), if the rubber plug is not compatible with the electrolyte, the components in the rubber plug will enter the electrolyte through the swelling effect. After the electrochemical corrosion in step 3), the leakage current at the aluminum stem position is the largest; harmful ions in the rubber plug enter the electrolyte through the swelling effect at the aluminum stem position of the anode needle, and then under the action of the electric field, harmful negative ions are enriched at the anode aluminum stem. Under the dual action of long time high temperature and electric field, the harmful ions will accelerate the corrosion of the aluminum stem oxide film, resulting in local flash or partial discharge. The high temperature generated by local flash will cause carbonization of the electrolyte at the interface, eventually causing the aluminum stem to appear black, and the aluminum stem surface will also appear slight etch pits. In order to verify, in this embodiment, a comparative experiment is set up, in which the rubber plug is not soaked in the electrolyte, and the other conditions are the same as in this embodiment. After the electrochemical corrosion in step 3), the single electrolyte will not cause the aluminum stem position of the anode needle to become black. That is, the blackening of the aluminum stem position of the anode needle is only possible when the rubber plug is not compatible with the electrolyte, and the components of the rubber plug enter the electrolyte.

[0026] If the rubber plug is compatible with the electrolyte, the amount of components in the rubber plug entering the electrolyte through the swelling effect will be very small, and after the electrochemical corrosion in step 3), the aluminum stem will not have the accumulation of rubber plug components, and will not become black.

[0027] The detection method of the corrosion resistance of the rubber plug in this embodiment is compared with the traditional high temperature durability / load test of more than 1000 hours, which is greatly shortened to only one day. At the same time, the detection method of the present application does not need to prepare a complete capacitor, only needs a rubber plug, an electrolyte and a simple test device, which saves a lot of material and manufacturing cost. In addition, the test method of this embodiment is suitable for rapid screening: it can quickly verify the compatibility of different rubber plugs and electrolytes in the material development stage, avoiding invalid formulations from entering mass production test.

Claims

1. A method for detecting the corrosion resistance of a rubber stopper, characterized by, The method comprises the following steps: 1) Soaking the rubber plug in the electrolyte for 3-10 hours; 2) Taking the electrolyte after step 1) and placing it in a detection container; taking the anode guide needle and the cathode guide needle so that the aluminum tongues of the anode guide needle and the cathode guide needle are immersed in the electrolyte; 3) Connecting the anode guide needle to the positive pole of the power supply and connecting the cathode guide needle to the negative pole of the power supply; applying a direct current voltage matching the highest voltage resistance of the electrolyte; continuing for 20-60 minutes; and the temperature is 105-130 DEG C; 4) Wiping the electrolyte on the surface of the anode guide needle; using a magnifying glass or a microscope to check whether there is corrosion and blackening phenomenon on the aluminum tongue and the aluminum stem of the anode guide needle; if there is, it is unqualified.

2. The method of claim 1, wherein: In step 1), the weight of the rubber plug is 10-40% of the weight of the electrolyte.

3. The method of claim 1, wherein the method is characterized by: In step 3), the anode guide needle and the cathode guide needle are fixed by the same rubber plug in step 1).

4. The method of claim 3, wherein the rubber stopper is a rubber stopper for a syringe. In step 3), the aluminum stem of the anode guide needle and the cathode guide needle is fixed in the lead hole of the rubber plug.

5. The method of claim 3, wherein the method is characterized by: In step 1), the rubber plug immersed in the electrolyte is cut into particles.

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