??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。

电容器的基本参数：

● 电容容量：70F ● 耐压：3.8V

??使用DM3068测量电容两端的电压。电压值为： U0=3.647V 。

??用电阻放电电容器。

放电电阻：

电阻：22Ω 功率：1/8 W

??120秒内记录100个放电数据点。

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]

  选择测量数据曲线上两个数据点。粗略计算电容的容量。

• 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。

  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]

  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。

  利用可编程电源对于法拉电容进行充电。

  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。

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？

■ 相关文献链接:

• 它的特点
• 法拉电容3.8V 10F/40F/100F/120F/250F/500F/750F 锂离子电容 D型

● 相关图表链接:

• 图1.1 锂离子法拉电容
• 图1.2 锂离子电容器管脚绝缘套
• 图1.3 使用电阻对于电容进行放电
• 表1-1 放电电容数据点
• 图1.6 电容放电曲线
• 表1-2 电容放电两个时间数据
• 16-充电电流与电压
• 充电电流曲线