Bipolar aluminum electrolytic capacitor for the ho

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Bipolar aluminum electrolytic capacitor for color TV set

Chinese Library Classification No.: tm535.2 document identification code: a Article No.: (1999) the bipolar aluminum electrolytic capacitor mass produced by our factory is specially equipped for large screen color TV sets of national famous brands such as Changhong and Konka. This product is used for horizontal deflection correction circuit of TV sets. Previously, most color TV sets factories used imported parts. In the past two years, the output of large screen color TV sets has increased rapidly. Due to price, supply channels and other reasons, the situation that the whole machine factory completely depends on imported parts has been broken. Domestic bipolar aluminum electrolytic capacitors with reliable quality have broad prospects for development. CDs bipolar aluminum electrolytic capacitor is characterized by non polarity, low loss, high temperature resistance (105 ℃) and high ripple current resistance. According to the needs of users and the standards of nicnicnicon in Japan in 1993, combined with the actual production, our factory has formulated the main performance indicators of CDs products (table 1-2). 1 product design principle 1.1 105 ℃ long-life type with special automatic centering device

under high temperature, the internal chemical reaction and physical process of the capacitor are accelerated, resulting in accelerated aging and shortened service life of the electrolytic capacitor. Therefore, when designing CDs type 105 ℃ long-life products, we must try to suppress the internal chemical reactions and physical processes. Specifically, the main chemical reactions are: the reaction between anodic oxide film and electrolyte, and the aging of electrolyte and sealing materials. In addition, when the applied voltage is applied, there is an electrochemical reaction on the capacitor electrode. The physical processes include evaporation of electrolyte, diffusion through rubber seal, conductivity and breakdown of anodic oxide film. In addition to the above situations, the Tg of the product shall be reduced as far as possible when the design 1 is to cut the rubber behind the rubber wrapping roll and mix the long-life product with a uniform temperature of 05 ℃ δ, To reduce the product temperature rise

1.2 ripple current resistant type

cds products are of large ripple current resistant type, so their ability to withstand AC load should be fully considered when designing products. Table 1 Comparison between main performance indexes of CDs capacitor and Nichicon standard item CDs performance 1993 Nichicon standard operating temperature range/℃ -25 ~ + ~ +85 allowable deviation of nominal capacitance/% +20+10 leakage current IL (5 min, bidirectional)/μ A≤100 ≤100tg δ ≤ 0.05 ≤ 0.05 low temperature characteristic (100 Hz)

z-25 ℃/z+20 ℃ ≤ 3 - durability 105 ℃, 1000 h load

il not greater than the specified value

tg δ Not more than 2 times the specified value

| △ c.c-1 | ≤ 15%70 ℃, 1000 h load

il not more than the specified value

tg δ Not more than 2 times the specified value

| △ c.c-1 | ≤ 15% high temperature storage 105 ℃, no load for 500 hours

il not more than 2 times the specified value

tg δ Not more than 2 times of the specified value

| △ c.c-1 | ≤ 15%85 ℃, 500 h no-load

il not more than 2 times of the specified value

tg δ Not more than 2 times the specified value

| △ c.c-1 |≤ 15% Table 2 CDs nominal capacitance, overall dimension and rated ripple current table Cr/μ F × Effective value of l/mm ripple current i/a

(105 ℃, 15.75 kHz) 4.712 × two hundred and fifty-two point zero one zero one six × two hundred and fifty-three point zero two two one six × three hundred and fifty-three point five three three one six × 404.0 note: the rated voltage of the product is 100 v. the shell number is formulated according to the standard of Nichicon company in 1993 (slightly smaller), and the ripple current is equivalent to the standard of Nichicon company. According to the power loss formula of aluminum electrolytic capacitor: p=i2 ~ r+il 2Rj ≈ I2, and its product finally uses a kind of product called stereolithography ~ R (1). In the formula: I ~ is the AC effective value through the capacitor; R is the equivalent series resistance of electrolytic capacitor; Il is the leakage current of the product; RJ is the insulation resistance of the product

generally, I-I ~, so formula (1) is written as: p=i2 ~ r (2) because the heat dissipation power is: P ′= α S Δ T (3), where: α Is the heat dissipation coefficient; S is the heat dissipation area; Δ T is the product temperature rise

according to the principle of heat balance: p=p ′ I2 ~ R= α S Δ T (4) gets: (5)

according to TG δ=ω Cr (6)

from equations (5) and (6):

(7) where: TG δ Is the loss tangent of the product; ω Angular frequency when working for the product; C is the capacitance of the product

according to formula (7), to improve the ripple resistance of the product, it is necessary to improve the heat dissipation coefficient and heat dissipation area of the product, improve the temperature rise resistance of the product, and reduce the Tg of the product δ。 2. According to the above analysis, CDs products with long service life of 105 ℃ and high ripple current resistance shall be designed according to the following requirements

2.1 select heat-resistant materials, such as high boiling point, non-aqueous or less aqueous working electrolyte. Under the condition of high temperature (105 ℃), the material yield strength performance of working electrolyte must be stable. At present, the working electrolyte of our factory is developed based on the above considerations. The main solvents are ethylene glycol and γ- Butyrolactone mixed solution, the main solute is quaternary ammonium salt, etc. A little hydrogen absorbent and stabilizer are added, and the working electrolyte resistivity is 230 ~ 270 Ω Cm, pH value 6 ~ 6.8, flash voltage us (tested at 85 ℃) is greater than 350 v. The electrolyte is characterized by low vapor pressure, high oxidation efficiency and strong permeability

2.2 use sealing rubber plugs with good solvent resistance to delay the chemical reaction of working electrolyte to sealing materials. In this regard, the butyl rubber widely used at present is better than ethylene propylene diene rubber

2.3 the anode foil shall be high-temperature and high current density enabling foil, and the anodic oxide film shall be

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