Measurements of ageing and thermal conductivity in a secondary NMC-hard carbon Li-ion battery and the impact on internal temperature profiles
Measurements of ageing and thermal conductivity in a secondary NMC-hard carbon Li-ion battery and the impact on internal temperature profiles
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DOI：
10.1016/j.electacta.2017.07.173
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发表时间：
2017-10-01
影响因子：
6.6
通讯作者：
Burheim, Odne Stokke
中科院分区：
文献类型：
--
作者：
Richter, Frank;Vie, Preben J. S.;Burheim, Odne Stokke
研究了75个具有LiNiMnCoO 2垂直棒硬碳化学的商用锂离子二次电池长达4年的老化。额定容量为17.5 Ah。电池在不同的电流速率和不同的充电状态之间循环。在不同温度和不同充电状态下进行了货架研究。老化温度在18-55 ℃之间变化。特定的欧姆电阻作为健康状态，老化温度和老化时间的函数。我们发现，在较高的温度下，电池耐受较少的循环。在较高温度下储存的容量损失也以可预测的方式增加。我们观察到，在存储的时刻的充电状态是非常重要的放电容量的损失。在存在和不存在电解质溶剂的情况下以及在不同的压实压力下测量原始和老化电极的热导率。发现对于干电极活性材料，热导率的范围为0.14-0.41 WK-1 m（-1），对于电解质溶剂浸泡的电极活性材料，热导率的范围为0.52-0.73 WK-1 m（-1）。电极材料的热导率没有随着老化而显著变化，但是在剩余电池容量和增加的欧姆电阻之间看到了强相关性。为了评估这些变化的影响，将测量结果用于一维模型中以计算电池内部温度。温度曲线作为放电率（2C -10 C）和老化时间（0 - 4年）的函数进行计算。该模型表明，在老化过程中，内部温度可以从100%容量的原始健康状态升高约2.5倍至58%容量。(C)2017爱思唯尔有限公司版权所有
The ageing of 75 commercial Li-ion secondary batteries with LiNiMnCoO2 vertical bar hard carbon chemistry was studied up to 4 years. The nominal capacity was 17.5 Ah. The batteries were cycled at different current rates and between different states of charge. Shelf studies were carried out at different temperatures and at different states of charge. The ageing temperature varied from 18-55 degrees C. The specific ohmic resistance was obtained as a function of state of health, ageing temperature, and ageing time. We found that the cell tolerated less cycles at higher temperatures. The loss of capacity also increased for storage at higher temperatures, in a predictable manner. We observed that the state of charge at the moment of storage was very important for the loss of discharge capacity. Thermal conductivities of pristine and aged electrodes were measured in the presence and absence of electrolyte solvent and under different compaction pressures. The thermal conductivity was found to range from 0.14-0.41 WK-1 m(-1) for dry electrode active material and from 0.52-0.73 WK-1 m(-1) for electrolyte solvent-soaked electrode active material. The thermal conductivity of the electrode materials did not change significantly with ageing, but a strong correlation was seen between remaining battery capacity and increasing ohmic resistance. To assess the impact of these changes, the measured results were used in a one-dimensional model to compute the battery internal temperature. Temperature profiles were computed as a function of discharging rate (2C - 10C) and ageing time (0 - 4 years). The model showed that the internal temperature can raise by a factor about 2.5 during ageing from the pristine state of health at 100 % to 58 % capacity. (C) 2017 Elsevier Ltd. All rights reserved.