Stress evolution and capacity fade in constrained lithium-ion pouch cells
Stress evolution and capacity fade in constrained lithium-ion pouch cells
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DOI：
10.1016/j.jpowsour.2013.06.165
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发表时间：
2014-01-01
影响因子：
9.2
通讯作者：
Arnold, Craig B.
中科院分区：
文献类型：
--
作者：
Cannarella, John;Arnold, Craig B.
通过监测循环过程中受限商用锂离子袋状电池的堆压和容量，研究了机械应力对锂离子电池寿命的影响。发现堆应力是一个动态量，随充放电而波动，并随循环长时间不可逆地逐渐增加。初始堆叠压力是一个重要的可控制造参数，其变化会在电池寿命期间产生不同的应力演化特征。研究发现，在较高的堆叠压力水平下制造的电池具有较短的循环寿命，尽管少量的堆叠压力会导致容量保持比无约束的电池增加。这些细胞的死后分析表明力学和电化学之间存在耦合，其中较高水平的机械应力导致较高的化学降解率，而层脱层导致未受约束的细胞的容量衰退。在所有电池中也观察到局部的隔板变形导致不均匀的锂运输。(C) 2013 Elsevier B.V.版权所有
The effects of mechanical stress on lithium-ion battery life are investigated by monitoring the stack pressure and capacity of constrained commercial lithium-ion pouch cells during cycling. Stack stress is found to be a dynamic quantity, fluctuating with charge/discharge and gradually increasing irreversibly over long times with cycling. Variations in initial stack pressure, an important controllable manufacturing parameter, are shown to produce different stress evolution characteristics over the lifetime of the cells. Cells manufactured with higher levels of stack pressure are found to exhibit shorter cycle lives, although small amounts of stack pressure lead to increased capacity retention over unconstrained cells. Postmortem analysis of these cells suggests a coupling between mechanics and electro-chemistry in which higher levels of mechanical stress lead to higher rates of chemical degradation, while layer delamination is responsible for the capacity fade in unconstrained cells. Localized separator deformation resulting in nonuniform lithium transport is also observed in all cells. (C) 2013 Elsevier B.V. All rights reserved.