Electrode and method for producing the same
View Patent ↗The electrode of the present invention includes a current collector and an active material-containing layer formed on one side or both sides of the current collector. The active material-containing layer has a thickness of 20 to 200 μm per one side of the current collector, and diethyl carbonate permeates the active material-containing layer at a rate of 0.1 g/(cm 2 ·min) or higher. Further, the method for producing an electrode of the present invention includes the steps of: forming an electrode precursor by forming an active material-containing layer on one side or both sides of a current collector; and compressing the electrode precursor. In the electrode precursor forming step, the active material-containing layer is formed such that the active material-containing layer has a higher porosity in a portion close to the current collector then in other portions.
1. A method for producing an electrode consisting of an active material-containing single layer, comprising the steps of:
forming an electrode precursor including an active material-containing layer by uniformly applying a paint for forming an active material-containing layer once to one side or both sides of a current collector so that an active material-containing single precursor layer having a uniform porosity is formed on one side or both sides of the current collector, and then drying the active material-containing single precursor layer internally with an infrared heater including a filament-type heating element; and
compressing the electrode precursor,
wherein when the surface of the current collector on which the active material-containing single layer is formed is given as a first datum,
the active material-containing single layer is marked off every 5 μm from the first datum by planes parallel to the first datum, and the plane parallel to and located 5 μm from the first datum is given as a second datum,
the average porosity of a part of the active material-containing single layer located 5 to 10 μm from the first datum is given as Va %, and the highest of average porosities measured every 5 μm range between the second datum and the surface of the active material-containing single layer not opposing the current collector is given as Vm %, the active material-containing single layer is formed in the electrode precursor forming step so that the following formulae (1) and (2) hold:
Va≧ 16% (1)
Va/Vm≧ 0.98 (2).
2. The method according to claim 1 , wherein the following formulae (3) and (4) hold:
36%≧ Va≧ 16% (3)
1.00≧ Va/Vm≧ 0.98 (4).
3. The method according to claim 1 , wherein the active material-containing single layer has a thickness of 20 to 200 urn per one side of the current collector in the compression step.
4. The method according to claim 1 , wherein when the active material-containing single layer is a positive electrode active material-containing layer, the positive electrode active material-containing layer has a density of 2.0 to 3.8 g/cm 3 in the compression step.
5. The method according to claim 1 , wherein when the active material-containing single layer is a negative electrode active material-containing layer, the negative electrode active material-containing layer has a density of 1.2 to 1.9 g/cm 3 in the compression step.