在回流焊接時，電容器頂部的zui高溫度不得超過 T（℃）所限定的溫度。無 鉛 焊 料 產 品 的 回 流 焊 條 件

^l Recommended Conditions for Reflow Soldering 無鉛焊料產品遵循的回流焊條件 （1） Preheat shall be made at 100℃~200℃ and for maximum 180 seconds.

100℃~200℃的預熱時間不得超過 180 秒鐘。

（2） Period that temperature at top of capacitor becomes more than 200℃and 230℃shall not exceed t and t1 seconds, respectively.

電容器頂部溫度高于 200℃和 230℃的時間，分別不得超過 t 和 t1 所限定的時間。

（3） Temperature at top of capacito

^l Temperature/Time profile 回流焊溫度與時間曲線圖

Peak temperature

t1 sec Max t sec Max

Preheat 180sec Max

Time (second)

X

ALUMINUM ELECTROLYTIC CAPACITORS'LIFE

關于鋁電解電容器的壽命

The life of non-solid aluminum electrolytic capacitors is mainly dependent on environmental conditions (e.g. ambient temperature, humidity etc.) and electrical factors(e.g. operating voltage, ripple current etc.).Generally, the wear-out mechanism of non-solid aluminum electrolytic capacitors is based on evaporation of electrolyte through the rubber seal. Consequently, the factor of temperature (ambient temperature and internal heating due to ripple current) is the most critical to electrolytic capacitor life. The effect of voltage on capacitor life is negligible, especially for low voltage electrolytic capacitors. The lifetime of non-solid aluminum electrolytic capacitors can be expressed as following equations:

非固體鋁電解電容器的壽命主要依賴于使用環(huán)境條件(如環(huán)境溫度,濕度等)和電負荷情況

(如工作電壓,紋波電流等)。通常而言,非固體鋁電解電容器的失效機理被認為是電解液通過 膠塞逐漸揮發(fā)導致的。因此,溫度因素(環(huán)境溫度及由于紋波電流而引起的內熱)對電解電容 器壽命有重大影響。相反,電壓對電容器壽命的影響可以忽略，尤其對于低壓電解電容器而 言更是如此。非固體鋁電解電容器的壽命可以用下列公式估算:

Le=Lo·Kt·Kr Where 這里

Le expected life at operating temperature Te (h)

在工作溫度 Te℃下的預期壽命(h)

Lo specified life at maximum operating temperature To (h)

在zui大工作溫度 To℃下的保證壽命(h)

Kt ambient temperature acceleration term

環(huán)境溫度影響因子

Kr ripple current acceleration term

紋波電流影響因子

_{Kt= Lo·A}(To-Te)/10

Where 這里

T_o maximum rated operating temperature(℃)

zui大額定工作溫度(℃)

T_e actual ambient temperature(℃)

實際環(huán)境使用溫度(℃)

A acceleration coefficient (For the range 35℃ to the maximum operating temperature, A≈

2)

加速系數(對于從 35℃到zui高工作溫度的范圍, A≈2)

_Kr=2(-△T/5)

Where 這里

△T an increase in core temperature by internal heating due to ripple

current(℃)

由于紋波電流引起的內熱造成電容器芯子的溫升(℃)

(△T=core temperature-ambient temperature

芯子濕度-環(huán)境濕度)

△T can be estimated as follows △T 可用以下公式估算:

△T= (i²·R)(β ·S)

Where 這里

i ripple current (A rms)

通過電容器的紋波電流(A rms)

• equivalent series resistance of the capacitor(Ω )

電容器的等效串聯電阻(Ω )

• heat radiation coefficient(W/℃·cm²)

鋁殼的熱輻射系數(W/℃·cm²)

• surface area of the capacitor (cm²)

電容器的表面積(cm²)

The expected life of the capacitor at lower temperature neglect of ripple current effect is shown in the following figure.

當忽略紋波電流影響時,電容器在較低溫度下的預期壽命可參照下圖.

Quick Reference Guide of the Expected Life 預期壽命快速參考圖

Example: Where a 3000hrs/105℃ guaranteed product is used continuously at 60℃, it can be expected to have a life of 6 years.

例 如: 對于 105℃ 3000 小時的產品,如果在 60℃環(huán)境中連續(xù)使用,它的預