1. Field
A spirally-wound electrode assembly for a rechargeable lithium battery and a rechargeable lithium battery including the same are disclosed.
2. Description of the Related Art
A fluorine-based polymer such as polyvinylidene fluoride (PVDF) is widely used as a matrix polymer of a gel electrolyte for a rechargeable lithium battery. For example, a porous layer including the fluorine-based polymer on the surface of a separator has been formed, for example, by the following method.
A first method is to prepare a slurry by dissolving the fluorine-based polymer in an organic solvent such as N-methylpyrrolidone, dimethyl acetamide, acetone and/or the like. Subsequently, the slurry is coated on a separator or an electrode, and the fluorine-based polymer is phase-separated by using a poor solvent such as water, methanol, tripropylene glycol and/or the like to perforate the fluorine-based polymer and to form a coating layer on the separator or the electrode. A second method is to prepare heated slurry by dissolving the fluorine-based polymer in a heated electrolyte solution using a solvent such as dimethyl carbonate, propylene carbonate, ethylene carbonate and/or the like. Subsequently, the heated slurry is coated on a separator or an electrode to form a coating layer. Then, the coating layer is cooled down to gelate (gel) the fluorine-based polymer and to form a porous layer swollen by the electrolyte solution.
However, the separator having the porous layer on the surface in these methods shows an undesirable or insufficient slip and easily generates static electricity, and thus, is difficult to handle in a manufacturing process as compared with a separator having no porous layer. For example, when the separator is overlapped with band-shaped positive and negative electrodes to manufacture a spirally-wound electrode assembly, the separator has an undesirable or insufficient slip with the positive and negative electrodes, and thus, the spirally-wound electrode assembly may be distorted. When the spirally-wound electrode assembly is distorted, it may be difficult to house such spirally-wound electrode assembly in a case. Further, such distorted spirally-wound electrode assembly may result in an undesirable or insufficient cycle-life of a battery.
USPTO Backgrounds
USPTO Backgrounds