开元高科铝电解电容的使用寿命

在回流焊接时，电容器顶部的zui高温度不得超过 T（℃）所限定的温度。无 铅 焊 料 产 品 的 回 流 焊 条 件

^l Recommended Conditions for Reflow Soldering 无铅焊料产品遵循的回流焊条件 （1） Preheat shall be made at 100℃~200℃ and for maximum 180 seconds.

100℃~200℃的预热时间不得超过 180 秒钟。

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

电容器顶部温度高于 200℃和 230℃的时间，分别不得超过 t 和 t1 所限定的时间。

（3） Temperature at top of capacito

^l Temperature/Time profile 回流焊温度与时间曲线图

Peak temperature

t1 sec Max t sec Max

Preheat 180sec Max

Time (second)

X

ALUMINUM ELECTROLYTIC CAPACITORS'LIFE

关于铝电解电容器的寿命

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:

非固体铝电解电容器的寿命主要依赖于使用环境条件(如环境温度,湿度等)和电负荷情况

(如工作电压,纹波电流等)。通常而言,非固体铝电解电容器的失效机理被认为是电解液通过 胶塞逐渐挥发导致的。因此,温度因素(环境温度及由于纹波电流而引起的内热)对电解电容 器寿命有重大影响。相反,电压对电容器寿命的影响可以忽略，尤其对于低压电解电容器而 言更是如此。非固体铝电解电容器的寿命可以用下列公式估算:

Le=Lo·Kt·Kr Where 这里

Le expected life at operating temperature Te (h)

在工作温度 Te℃下的预期寿命(h)

Lo specified life at maximum operating temperature To (h)

在zui大工作温度 To℃下的保证寿命(h)

Kt ambient temperature acceleration term

环境温度影响因子

Kr ripple current acceleration term

纹波电流影响因子

_{Kt= Lo·A}(To-Te)/10

Where 这里

T_o maximum rated operating temperature(℃)

zui大额定工作温度(℃)

T_e actual ambient temperature(℃)

实际环境使用温度(℃)

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

2)

加速系数(对于从 35℃到zui高工作温度的范围, A≈2)

_Kr=2(-△T/5)

Where 这里

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

current(℃)

由于纹波电流引起的内热造成电容器芯子的温升(℃)

(△T=core temperature-ambient temperature

芯子湿度-环境湿度)

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

△T= (i²·R)(β ·S)

Where 这里

i ripple current (A rms)

通过电容器的纹波电流(A rms)

• equivalent series resistance of the capacitor(Ω )

电容器的等效串联电阻(Ω )

• heat radiation coefficient(W/℃·cm²)

铝壳的热辐射系数(W/℃·cm²)

• surface area of the capacitor (cm²)

电容器的表面积(cm²)

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

当忽略纹波电流影响时,电容器在较低温度下的预期寿命可参照下图.

Quick Reference Guide of the Expected Life 预期寿命快速参考图

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: 对于 105℃ 3000 小时的产品,如果在 60℃环境中连续使用,它的预