OPTIMIZATION OF POROSITY AND THICKNESS OF A BATTERY ELECTRODE BY MEANS OF A REACTION-ZONE MODEL
OPTIMIZATION OF POROSITY AND THICKNESS OF A BATTERY ELECTRODE BY MEANS OF A REACTION-ZONE MODEL
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DOI：
10.1149/1.2043956
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发表时间：
1995-01-01
影响因子：
3.9
通讯作者：
NEWMAN, J
中科院分区：
文献类型：
--
作者：
NEWMAN, J
如果电极动力学很快，浓度梯度可以忽略，则电池电极中的反应被限制在一个狭窄的区域内，该区域在电池放电时穿过电极。在此过程中，欧姆电阻增大，截止电位可能表示放电结束。希望电极的容量(因此其厚度)与放电时间t(D)匹配。假设存在特定的隔膜厚度，并且隔膜的电解液与渗透正电极的电解液相同，则可以获得最佳孔隙率，作为存在活性材料的愿望和具有通过电极的孔的传导路径的必要性之间的折衷。对于具有铝箔负极和与荷电状态无关的开路电位的体系，该最佳值取决于一个主要参数T=U kappa(S)t(D)/q(+)L(S)(2)，该参数涉及放电时间、开路电位U、隔膜的电导率kappa(S)、厚度L(S)和正极中每单位体积固体的容量Q(+)。还有一个参数：截止电势与开路电势之比。引入其他参数是为了说明电池的更复杂结构。
If electrode kinetics ape fast and concentration gradients can be ignored, the reaction in a battery electrode is confined to a narrow zone, which moves through the electrode as the battery is discharged. During this process, the ohmic resistance increases, and the cutoff potential may signal the end of the discharge. It is desirable to have a matching of the capacity of the electrode (and hence its thickness) with the time t(d) of discharge. Assuming that there is d certain specified separator thickness and that the electrolyte of the separator is the same as that permeating the positive electrode, it is possible to obtain the optimum porosity as a compromise between the desire to have active material present and the necessity to have a conduction path through the pores of the electrode. For a system with a foil negative electrode and an open-circuit potential which is independent of state of charge, this optimum value depends on one principal parameter T = U kappa(s)t(d)/q(+)L(s)(2), one which involves the time of discharge, the open-circuit potential U, the conductivity kappa(s), and thickness L(s) of the separator, and the capacity q(+) per unit volume of solids in the positive electrode. There is one other parameter: the ratio of the cutoff potential to the open-circuit potential. Other parameters are introduced to account for a more complex structure of the battery.