Modeling the degradation mechanisms of C6/LiFePO4 batteries

JOURNAL OF POWER SOURCES

卷:375

Article

Li, Dongjiang¹  Danilov, Dmitri L.^1,2  Zwikirsch, Barbara³  Fichtner, Maximilian³  Yang, Yong⁴  Eichel, Ruediger-A.^1,5  Notten, Peter H. L.^1,2,6 

[1] Forschungszentrum Julich, Fundamental Electrochem IEK 9, D-52425 Julich, Germany

[2] Eindhoven Univ Technol, Dept Elect Engn, NL-5600 MB Eindhoven, Netherlands

[3] Helmholtz Inst Ulm Electrochem Energy Storage HIU, D-89081 Ulm, Germany

[4] Xiamen Univ, Dept Chem, State Key Lab Phys Chem Solid Surfaces, Xiamen 361005, Peoples R China

[5] Rhein Westfal TH Aachen, D-52074 Aachen, Germany

[6] Eindhoven Univ Technol, Dept Chem Engn & Chem, NL-5600 MB Eindhoven, Netherlands

关键词: Li-ion batteries;    Modeling;    Solid-Electrolyte-Interface;    Capacity fade;    Material decay;   

DOI  :  10.1016/j.jpowsour.2017.11.049

来源: Elsevier

【 摘 要 】

A fundamental electrochemical model is developed, describing the capacity fade of Ce/LiFePO4 batteries as a function of calendar time and cycling conditions. At moderate temperatures the capacity losses are mainly attributed to Li immobilization in Solid-Electrolyte-Interface (SEI) layers at the anode surface. The SEI formation model presumes the availability of an outer and inner SEI layers. Electron tunneling through the inner SEI layer is regarded as the rate-determining step. The model also includes high temperature degradation. At elevated temperatures, iron dissolution from the positive electrode and the subsequent metal sedimentation on the negative electrode influence the capacity loss. The SEI formation on the metal-covered graphite surface is faster than the conventional SEI formation. The model predicts that capacity fade during storage is lower than during cycling due to the generation of SEI cracks induced by the volumetric changes during (dis)charging. The model has been validated by cycling and calendar aging experiments and shows that the capacity loss during storage depends on the storage time, the State-of-Charge (SoC), and temperature. The capacity losses during cycling depend on the cycling current, cycling time, temperature and cycle number. All these dependencies can be explained by the single model presented in this paper.

【 授权许可】

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