Analysis of the causes of excessive internal resistance in lithium-ion batteries
I. Process Aspects
(1) Insufficient conductive agent in the positive electrode formulation (poor conductivity between materials, because lithium cobalt itself has very poor conductivity).
(2) Excessive binder in the positive electrode formulation (binders are generally polymer materials with strong insulation properties)
(3) Excessive binder in the negative electrode formulation (binders are generally polymer materials with strong insulation properties)
(4) Uneven distribution of ingredients
(5) The binder solvent was not completely dissolved during the mixing process (it could not be completely dissolved in NMP and water).
II. Materials
(1) The positive electrode material has high resistance (poor conductivity, such as lithium iron phosphate).
(2) Influence of membrane material (membrane thickness, low porosity, small pore size)
(3) Influence of lithium-ion battery electrolyte materials (low conductivity, high viscosity)
(4) Influence of the positive electrode PVDF material (high quantity or large molecular weight).
