Correlation of Arrhenius behaviors in power and capacity fades with cell impedance and heat generation in cylindrical lithium-ion cells
Correlation of Arrhenius behaviors in power and capacity fades with cell impedance and heat generation in cylindrical lithium-ion cells
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DOI：
10.1016/s0378-7753(03)00196-4
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发表时间：
2003-06
影响因子：
9.2
通讯作者：
B. Liaw;E. Roth;R. Jungst;G. Nagasubramanian;H. Case;D. Doughty
中科院分区：
文献类型：
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作者：
B. Liaw;E. Roth;R. Jungst;G. Nagasubramanian;H. Case;D. Doughty
制作了一系列圆柱形18650锂离子电池，其结构为MAG-10|1.2M LiPF6碳酸酯：碳酸乙酯(w：w=3：7)|LixNi0.8Co0.15Al0.05O2，用于动力辅助混合动力电动汽车，在不同的温度和荷电状态老化条件下进行了测试。随着老化的进展，电池的功率容量、倍率容量和阻抗的变化被间歇性地表征。用Arrhenius方程描述了这些性质随温度的变化。我们发现，功率和容量衰落的退化似乎与电池中阻抗的增加有关。降解经历了一个多阶段的过程。降解初始阶段的活化能约为50-55kJ/mol，这是由按C/1速率测量的幂衰减和C_1电容衰减得出的。此外，在不同温度下，对两个单独的未老化细胞在80%SOC下进行微量热测量，以测量细胞中的静态热产生。我们发现，静态热产生的活化能在48-55kJ/mol数量级，与功率和C_1电容衰减得到的活化能相似。激活能大小的一致性表明，功率和C1电容的衰减与细胞内阻抗的变化有关，很可能是通过相同的衰落机制。这种褪色机制似乎与电池的静态热产生有关。
A series of cylindrical 18650 lithium-ion cells with an MAG-10|1.2M LiPF6ethylene carbonate (EC):ethyl methyl carbonate (EMC) (w:w=3:7)|LixNi0.8Co0.15Al0.05O2configuration were made and tested for power-assist hybrid electric vehicle (HEV) applications under various aging conditions of temperature and state-of-charge (SOC). The cells were intermittently characterized for changes in power capability, rate capacity, and impedance as aging progressed. The changes of these properties with temperature, as depicted by Arrhenius equations, were analyzed. We found that the degradation in power and capacity fade seems to relate to the impedance increase in the cell. The degradation follows a multi-stage process. The initial stage of degradation has an activation energy of the order of 50–55kJ/mol, as derived from power fade and C1capacity fade measured at C/1 rate. In addition, microcalorimetry was performed on two separate unaged cells at 80% SOC at various temperatures to measure static heat generation in the cells. We found that the static heat generation has an activation energy of the order of 48–55kJ/mol, similar to those derived from power and C1capacity fade. The correspondence in the magnitude of the activation energy suggests that the power and C1capacity fades were related to the changes of the impedance in the cells, most likely via the same fading mechanism. The fading mechanism seemed to be related to the static heat generation of the cell.