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電解電容廣泛應用在電力(li)電子的(de)不(bu)同領域，主(zhu)要是用于(yu)平滑(hua)、儲存能量或者(zhe)交(jiao)流(liu)電壓整流(liu)后(hou)的(de)濾(lv)波，另(ling)外還用于(yu)非精密的(de)時序延時等。在開關電源的(de)MTBF預計時，模型(xing)分析(xi)結(jie)果(guo)表明(ming)電解(jie)電容是影響開關電源壽(shou)命的(de)主(zhu)要因(yin)素，因(yin)此了(le)解(jie)、影響電容壽(shou)命的(de)因(yin)素非常重要。

1.電(dian)解電(dian)容(rong)的壽命(ming)取決于(yu)其內(nei)部溫度。

因此(ci)，電(dian)(dian)解(jie)電(dian)(dian)容(rong)的設計(ji)和應用(yong)條件都會影響到電(dian)(dian)解(jie)電(dian)(dian)容(rong)的壽命。從設計(ji)角(jiao)度，電(dian)(dian)解(jie)電(dian)(dian)容(rong)的設計(ji)方(fang)法、材(cai)料、加工工藝決定(ding)了(le)電(dian)(dian)容(rong)的壽命和穩定(ding)性(xing)。而對應用(yong)者來講(jiang)，使用(yong)電(dian)(dian)壓、紋(wen)波電(dian)(dian)流、開關頻率、安(an)裝(zhuang)形式(shi)(shi)、散熱方(fang)式(shi)(shi)等(deng)都影響電(dian)(dian)解(jie)電(dian)(dian)容(rong)的壽命。

2.電解電容的非正(zheng)常失效

一些因素會引起電(dian)(dian)(dian)(dian)解電(dian)(dian)(dian)(dian)容失效(xiao)，如極低的溫(wen)度，電(dian)(dian)(dian)(dian)容溫(wen)升(sheng)（焊接(jie)溫(wen)度，環境溫(wen)度，交流紋波），過高的電(dian)(dian)(dian)(dian)壓，瞬(shun)時電(dian)(dian)(dian)(dian)壓，甚高頻或反偏壓；其中溫(wen)升(sheng)是(shi)對電(dian)(dian)(dian)(dian)解電(dian)(dian)(dian)(dian)容工作壽命(Lop)影響最大(da)的因素。

電(dian)(dian)(dian)容(rong)的(de)(de)導(dao)電(dian)(dian)(dian)能(neng)力由電(dian)(dian)(dian)解(jie)液(ye)的(de)(de)電(dian)(dian)(dian)離(li)(li)能(neng)力和(he)(he)粘度決定(ding)。當(dang)溫度降(jiang)低(di)時(shi)，電(dian)(dian)(dian)解(jie)液(ye)粘度增加(jia)，因而離(li)(li)子移動性和(he)(he)導(dao)電(dian)(dian)(dian)能(neng)力降(jiang)低(di)。當(dang)電(dian)(dian)(dian)解(jie)液(ye)冷凍時(shi)，離(li)(li)子移動能(neng)力非常低(di)以致非常高的(de)(de)電(dian)(dian)(dian)阻。相反(fan)，過高的(de)(de)熱量將加(jia)速電(dian)(dian)(dian)解(jie)液(ye)蒸(zheng)發，當(dang)電(dian)(dian)(dian)解(jie)液(ye)的(de)(de)量減少到一定(ding)極(ji)限時(shi)，電(dian)(dian)(dian)容(rong)壽命也就(jiu)終止(zhi)了。在高寒地區（一般－25℃以下）工作時(shi)，就(jiu)需要進行加(jia)熱，保證電(dian)(dian)(dian)解(jie)電(dian)(dian)(dian)容(rong)的(de)(de)正常工作溫度。如室外型UPS，在我國東北地區都配(pei)有加(jia)熱板。

電(dian)(dian)容(rong)(rong)(rong)器在(zai)過壓(ya)(ya)狀(zhuang)態下容(rong)(rong)(rong)易被擊穿，而實際(ji)應用(yong)中(zhong)的(de)浪(lang)涌電(dian)(dian)壓(ya)(ya)和瞬時高(gao)電(dian)(dian)壓(ya)(ya)是(shi)(shi)經常出(chu)(chu)(chu)(chu)現的(de)。尤其我國幅員遼闊，各(ge)地電(dian)(dian)網復雜(za)，因此，交流(liu)電(dian)(dian)網很復雜(za)，經常會出(chu)(chu)(chu)(chu)現超出(chu)(chu)(chu)(chu)正常電(dian)(dian)壓(ya)(ya)的(de)30%，尤其是(shi)(shi)單相(xiang)輸(shu)(shu)入，相(xiang)偏會加重交流(liu)輸(shu)(shu)入的(de)正常范圍。經測試表明，常用(yong)的(de)450V/470uF105℃的(de)進口普通(tong)(tong)2000小時電(dian)(dian)解(jie)電(dian)(dian)容(rong)(rong)(rong)，在(zai)額(e)定電(dian)(dian)壓(ya)(ya)的(de)1.34倍電(dian)(dian)壓(ya)(ya)下，2小時后電(dian)(dian)容(rong)(rong)(rong)會出(chu)(chu)(chu)(chu)現漏液冒氣(qi)，頂(ding)部沖(chong)開。根據統計和分析(xi)，與(yu)電(dian)(dian)網接近的(de)通(tong)(tong)信開關電(dian)(dian)源(yuan)PFC輸(shu)(shu)出(chu)(chu)(chu)(chu)電(dian)(dian)解(jie)電(dian)(dian)容(rong)(rong)(rong)的(de)失效(xiao)，主要是(shi)(shi)由(you)于電(dian)(dian)網浪(lang)涌和高(gao)壓(ya)(ya)損(sun)壞。鋁電(dian)(dian)解(jie)電(dian)(dian)容(rong)(rong)(rong)的(de)電(dian)(dian)壓(ya)(ya)選擇一般進行二級(ji)降額(e)，降到額(e)定值的(de)80％使用(yong)較為合理。

3壽(shou)命影響因素分析

除了非正常的失(shi)效，電(dian)解(jie)電(dian)容(rong)的壽命與溫度有指數(shu)級的關(guan)系。因使用非固態電(dian)解(jie)液(ye)，電(dian)解(jie)電(dian)容(rong)的壽命還取(qu)決于(yu)電(dian)解(jie)液(ye)的蒸發(fa)速度，由此導致(zhi)的電(dian)氣性能降低。這些參(can)數(shu)包(bao)括電(dian)容(rong)的容(rong)值，漏電(dian)流和等(deng)效串聯(lian)電(dian)阻（ESR）。

參考RIFA公司預計壽命的公式(shi)：

PLOSS=(IRMS)2xESR（1）

Th=Ta+PLOSSxRth（2）

Lop=Ax2Hours（3）

B=參考溫度值（典(dian)型值為85℃）

A=參考溫(wen)度(du)下的(de)電容壽命（根據電容器直徑的(de)不同而變化）

C=導致電容壽命減(jian)少一半所需的(de)溫升度數

從(cong)上面的(de)(de)公式中(zhong)，我們可(ke)以明(ming)顯的(de)(de)看到(dao)，影響電(dian)(dian)解電(dian)(dian)容(rong)壽命(ming)的(de)(de)幾個直接因素：紋波(bo)電(dian)(dian)流(IRMS)和等效串聯(lian)電(dian)(dian)阻值（ESR）、環(huan)境(jing)(jing)溫(wen)(wen)度（Ta）、從(cong)熱點(dian)傳遞到(dao)周圍(wei)環(huan)境(jing)(jing)的(de)(de)總的(de)(de)熱阻（Rth）。電(dian)(dian)容(rong)內部溫(wen)(wen)度最高的(de)(de)點(dian)，叫(jiao)熱點(dian)溫(wen)(wen)度（Th）。熱點(dian)溫(wen)(wen)度值是影響電(dian)(dian)容(rong)工(gong)作壽命(ming)的(de)(de)主要因素。而下列因素又決定了熱點(dian)溫(wen)(wen)度值實際(ji)應(ying)用(yong)中(zhong)的(de)(de)外界溫(wen)(wen)度（環(huan)境(jing)(jing)溫(wen)(wen)度Ta）,從(cong)熱點(dian)傳遞到(dao)周圍(wei)環(huan)境(jing)(jing)的(de)(de)總的(de)(de)熱阻（Rth）和由(you)交流電(dian)(dian)流引起的(de)(de)能量(liang)損耗（PLOSS）。電(dian)(dian)容(rong)的(de)(de)內部溫(wen)(wen)升與(yu)能量(liang)損耗成(cheng)線(xian)形(xing)關系。

電(dian)(dian)(dian)容充放電(dian)(dian)(dian)時(shi)(shi)，電(dian)(dian)(dian)流(liu)在(zai)流(liu)過(guo)電(dian)(dian)(dian)阻時(shi)(shi)會引起(qi)能(neng)量損(sun)耗，電(dian)(dian)(dian)壓的變化(hua)在(zai)通過(guo)電(dian)(dian)(dian)介質(zhi)時(shi)(shi)也會引起(qi)能(neng)量損(sun)耗，再加上漏電(dian)(dian)(dian)流(liu)造成(cheng)的能(neng)量損(sun)耗，所有(you)的這(zhe)些損(sun)耗導(dao)致的結果是電(dian)(dian)(dian)容內部溫度升高(gao)。