锂离子电容
Posted 卓晴
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简 介: 对于购买到的70F的离子电容进行初步测试,获得它的基本特性。
关键词
: 离子电容,充电,放电
§01 锂离子法拉电容
锂离子电容(Li-ion Capacitor :LIC),也叫做电化学混合电容器(EHC),非对称电化学电容器,是一种结余超级电容和电池之间的星星储能元件。它具有比超级电容器更高的比电容和比能量即比电池更好的功率密度。
它的特点 :
- 拥有更高的功率密度,在大电流应用场合特别是高能脉冲环境,可以更好地满足功率要求;
- 具有结余双电层电容器和蓄电池之间的比能量;
- 充放电循环时间很短,远远小于蓄电池的重放循环时间;
- 可以满足长期使用,无需维护
今天购买到的 法拉电容3.8V 10F/40F/100F/120F/250F/500F/750F 锂离子电容 D型 到货了,下面对其进行测试。
▲ 图1.1 锂离子法拉电容
1、测量静态特性
下面刚刚到货的锂离子电池,可以看到它们的正极(管脚长)已经被绝缘套了。
-
电容的基本参数:
-
● 电容容量
:70F
● 耐压
:3.8V
▲ 图1.2 锂离子电容器管脚绝缘套
(1)测量电容两端电压
使用DM3068测量电容两端的电压。电压值为: U0=3.647V
。
(2)电容放电
使用电阻对于电容进行放电。
-
放电电阻:
-
电阻
:22Ω
功率
:1/8 W
▲ 图1.3 使用电阻对于电容进行放电
记录下放电120秒内100个数据点。
▲ 图1.4 使用电阻对于电容进行放电曲线
tdim=[0.0000,1.1691,2.3401,3.5662,4.7603,5.9503,7.2034,8.3925,9.5935,10.8126,12.0247,13.2548,14.4438,15.6359,16.8870,18.0780,19.2981,20.4982,21.7062,22.9353,24.1274,25.3184,26.5715,27.7596,28.9717,30.1797,31.3698,32.6219,33.8119,35.0350,36.2341,37.4421,38.6702,39.8643,41.0603,42.2864,43.4945,44.7216,45.9166,47.1027,48.3528,49.5558,50.7369,51.9750,53.1780,54.3941,55.5992,56.7792,58.0343,59.2284,60.4475,61.6525,62.8316,64.0877,65.2797,66.5058,67.7019,68.9079,70.1230,71.3471,72.5221,73.7712,74.9643,76.1824,77.3834,78.5675,79.8216,81.0166,82.2347,83.4368,84.6198,85.8729,87.0670,88.2870,89.4881,90.7062,91.9073,93.1203,94.3044,95.5385,96.7505,97.9756,99.1727,100.3567,101.6088,102.8019,104.0239,105.2210,106.4311,107.6572,108.8732,110.0513,111.2924,112.4854,113.7065,114.9036,116.0906,117.3427,118.5378,119.7238]
vdim=[3.5328,3.5292,3.5257,3.5225,3.5193,3.5163,3.5134,3.5105,3.5078,3.5051,3.5024,3.4998,3.4972,3.4947,3.4923,3.4898,3.4874,3.4850,3.4826,3.4803,3.4780,3.4757,3.4734,3.4711,3.4688,3.4666,3.4644,3.4621,3.4599,3.4578,3.4556,3.4534,3.4512,3.4491,3.4469,3.4448,3.4427,3.4405,3.4384,3.4363,3.4342,3.4321,3.4300,3.4279,3.4259,3.4238,3.4217,3.4197,3.4176,3.4156,3.4135,3.4115,3.4094,3.4074,3.4054,3.4033,3.4013,3.3993,3.3973,3.3953,3.3933,3.3913,3.3893,3.3873,3.3853,3.3833,3.3813,3.3793,3.3773,3.3754,3.3734,3.3714,3.3694,3.3675,3.3655,3.3635,3.3616,3.3596,3.3577,3.3557,3.3538,3.3518,3.3499,3.3479,3.3460,3.3441,3.3421,3.3402,3.3383,3.3364,3.3344,3.3325,3.3306,3.3287,3.3267,3.3248,3.3229,3.3210,3.3191,3.3172]
(3)通过测量计算电容
选择测量数据曲线上两个数据点。粗略计算电容的容量。
数据点 | 时间 | 电压 |
---|---|---|
第一个数据点 | 20s | 3.4867V |
第二个数据点 | 120s | 3.3179V |
-
放电容量: Q = T ⋅ U 1 + U 2 2 ⋅ 1 R = 100 × 3.4867 + 3.3179 2 × 1 22 = 15.465 Q = T \\cdot {{U_1 + U_2 } \\over 2} \\cdot {1 \\over R} = 100 \\times {{3.4867 + 3.3179} \\over 2} \\times {1 \\over {22}} = 15.465\\,\\, Q=T⋅2U1+U2⋅R1=100×23.4867+3.3179×221=15.465
-
电压变化: Δ U 12 = 3.4867 − 3.3179 = 0.1688 V \\Delta U_{12} = 3.4867 - 3.3179 = 0.1688V ΔU12=3.4867−3.3179=0.1688V
-
电容容量: C = Q Δ U = 15.465 0.1688 = 91.673 F C = {Q \\over {\\Delta U}} = {{15.465} \\over {0.1688}} = 91.673\\,\\,F C=ΔUQ=0.168815.465=91.673F
上面测量估算的电容笔电容器的标称职(70F)大。有可能是因为放电电阻功率小,放电温升引起电阻增加,减少了放电电流。
(4)使用大功率电阻进行放电
使用大功率电阻。电阻的参数:
-
▲ 电阻参数:
-
● 电阻
:20.6Ω
● 功率
:15W
tdim=[0.0000,1.2081,2.3831,3.6362,4.8283,6.0523,7.2494,8.4375,9.6936,10.8806,12.1047,13.2988,14.4868,15.7429,16.9310,18.1550,19.3831,20.5632,21.7912,22.9833,24.1724,25.4265,26.6155,27.8376,29.0347,30.2217,31.4758,32.6669,33.8619,35.1110,36.2981,37.5251,38.7182,39.9183,41.1434,42.3494,43.5725,44.7686,45.9576,47.2107,48.4008,49.5948,50.8429,52.0330,53.2540,54.4521,55.6402,56.8963,58.0843,59.3034,60.5215,61.6945,62.9266,64.1357,65.3247,66.5578,67.7669,68.9919,70.1870,71.3811,72.6302,73.8172,75.0093,76.2624,77.4494,78.6745,79.8686,81.0666,82.3147,83.4998,84.6958,85.9429,87.1310,88.3591,89.5551,90.7372,91.9893,93.3743,94.7824,96.0305,97.2206,98.4436,99.6387,100.8498,102.0618,103.2699,104.4630,105.7110,106.9011,108.1292,109.3213,110.5123,111.7634,112.9505,114.1735,115.3726,116.5587,117.8137,119.0028,120.2059]
vdim=[3.3096,3.3058,3.3022,3.2988,3.2955,3.2924,3.2894,3.2865,3.2837,3.2809,3.2782,3.2756,3.2730,3.2704,3.2679,3.2654,3.2630,3.2606,3.2582,3.2558,3.2534,3.2511,3.2488,3.2465,3.2442,3.2419,3.2396,3.2374,3.2351,3.2329,3.2307,3.2285,3.2263,3.2241,3.2219,3.2197,3.2176,3.2154,3.2132,3.2111,3.2089,3.2068,3.2047,3.2026,3.2004,3.1983,3.1962,3.1941,3.1920,3.1899,3.1878,3.1857,3.1836,3.1816,3.1795,3.1774,3.1753,3.1733,3.1712,3.1691,3.1671,3.1650,3.1630,3.1609,3.1588,3.1568,3.1547,3.1527,3.1506,3.1486,3.1466,3.1445,3.1425,3.1404,3.1384,3.1364,3.1343,3.1316,3.1296,3.1276,3.1256,3.1235,3.1215,3.1195,3.1175,3.1155,3.1134,3.1114,3.1094,3.1074,3.1054,3.1034,3.1014,3.0993,3.0973,3.0953,3.0933,3.0913,3.0893,3.0873]
▲ 图1.6 电容放电曲线
数据点 | 时间 | 电压 |
---|---|---|
第一个数据点 | 20s | 3.2628V |
第二个数据点 | 120s | 3.088V |
利用上面两个数据计算电容的容量:
C = Q Δ U = 3.2628 + 3.088 2 ⋅ 100 20.6 ⋅ 1 3.2628 − 3.088 = 88.18 F C = {Q \\over {\\Delta U}} = {{3.2628 + 3.088} \\over 2} \\cdot {{100} \\over {20.6}} \\cdot {1 \\over {3.2628 - 3.088}} = 88.18F C=ΔUQ=23.2628+3.088⋅20.6100⋅3.2628−3.0881=88.18F
对比上面两次测量结果,电容的容量大体等于90F。
§02 充电电流
利用可编程电源对于法拉电容进行充电。
1、充电曲线
使用DH1766输出设定3.8V,对电容进行充电。充电过程如下图所示。
▲ 16- 充电电流与电压
▲ 充电电流曲线
※ 测试结果 ※
测量了刚刚购买到的锂离子法拉电容,它具有初始的充电电压。大约是3.6V左右。通过放电,测量它的电容大约是90F左右。
通过恒压源对法拉电容进行充电,充电过程类似于普通电容的充电特性。
那么这种电容是否允许放电到0?它的耐压又最大能够达到多少呢?
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