Diffusion induced stress in layered Li-ion battery electrode plates
Diffusion induced stress in layered Li-ion battery electrode plates
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DOI：
10.1016/j.jpowsour.2012.02.104
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发表时间：
2012-07
影响因子：
9.2
通讯作者：
Junqian Zhang;B. Lu;Yicheng Song;Xiang-yin Ji
中科院分区：
文献类型：
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作者：
Junqian Zhang;B. Lu;Yicheng Song;Xiang-yin Ji
本文采用扩散诱导应力的解析表达式，对层状锂离子电池极板的结构形态进行了评价。讨论了对称电极和非对称双层电极。分析了集流体与活性板的厚度比和模量比是影响应力的重要参数。采用具有较小弹性模量的材料作为集流体可以降低集流体和活性板中的峰值应力。增大集流体的厚度会减小集流体本身的应力，但会增大活性板的应力。因此，从设计电极的机械观点来看，用于集电器的材料应该尽可能柔软和柔性。集流体的厚度应在适当的范围内。基本上，在满足机械强度的前提下，应尽可能小。最后讨论了均匀、恒电流、恒电位三种充电条件对扩散应力的影响。发现三种情况下的最大应力与嵌入锂离子的总量呈线性关系。基于应力，建议了一种优化的充电操作，即先恒电流再恒电位。
In this paper, structural configuration of layered Li-ion battery electrode plates is evaluated by analytically formulating the diffusion induced stress. Both symmetric electrode and asymmetric bilayer electrode are discussed. The thickness ratio and the modulus ratio of current collector to active plate are analytically identified to be the important influence parameters on the stress. Applying a material with smaller elastic modulus for current collector could reduce the peak stresses in both current collector and active plate. Increasing the thickness of current collector would reduce the stress in itself while promote the stress in active plate. Therefore, from mechanical viewpoint on designing an electrode, the material for current collector should be as soft and flexible as possible. And the thickness of current collector should be in an appropriate range. Basically, it should be as small as possible on the precondition that the mechanical strength is satisfied. Finally, effects of three charging conditions, i.e. uniform, galvanostatic, and potentiostatic, on the diffusion induced stress is discussed. It is found the maximum stresses for three cases are linear to the total amount of intercalated lithium ions. Based on the stresses, an optimized charging operation, i.e. first galvanostatic followed by potentiostatic, is suggested.