2022 Volume 71 Issue 12 Pages 989-996
The macroscopic creep properties of negative electrode for lithium-ion batteries and their estimation method have been investigated based on the microscopic structure of the electrode. Tensile tests and creep tests were conducted on the negative electrode consisting of carbon powder and polyvinylidene fluoride (PVDF) binder. The stress-strain curve, the time history of the tensile strain and the creep rupture time were measured in these tests and estimated by using a simple model proposed in this study. The proposed model approximates the alignment of the carbon particles as body-centered cubic (bcc) and face-centered cubic (fcc). The external load on the model is supported by the PVDF binder located between the carbon particles. The test results show that the macroscopic mechanical properties including the creep properties of the negative electrode were affected by the mechanical properties of the PVDF binder. The stress-strain curve and the time history of the tensile strain located between the upper limit and the lower limit of the proposed model. The tensile strength and the creep rupture time agreed with the lower limit of the proposed model.
