Electrode quality evaluation method and electrode manufacturing method
Provided is a method of evaluating electrode quality capable of simply and quickly filtering out defective electrodes by measuring a color coordinate value of electrodes before roll-pressing, which specifically includes: providing an electrode which includes a current collector and an active material layer formed on the current collector and has not been roll-pressed; measuring a color coordinate value of the active material layer using an optical instrument; and evaluating the electrode as a good product when the measured color coordinate value satisfies a predetermined electrode quality evaluation criterion and as defective when the measured color coordinate value does not satisfy the predetermined electrode quality evaluation criterion.
1. A method of evaluating quality of an electrode comprising a current collector and an active material and not being rolled, comprising:
measuring a color coordinate value of the active material layer using an optical instrument; and
evaluating the quality of the electrode as a good product when the color coordinate value satisfies a predetermined electrode quality evaluation criterion and as defective when the color coordinate value does not satisfy the predetermined electrode quality evaluation criterion.
2. The method of claim 1 , wherein the color coordinate value is an L* value, and the predetermined electrode quality evaluation criterion for the L* value is 35.4 or more.
3. The method of claim 1 , wherein the color coordinate value is an a value, and the predetermined electrode quality evaluation criterion for the a* value is 0.78 or more.
4. The method of claim 1 , wherein the color coordinate value is a whiteness value, and the predetermined electrode quality evaluation criterion for the whiteness value is 7 or more.
5. The method of claim 1 , wherein the optical instrument is a spectrophotometer or a colorimeter.
6. The method of claim 5 , wherein the colorimeter is a contact colorimeter or a non-contact colorimeter.
7. A method of manufacturing an electrode, comprising:
forming an active material layer by applying a slurry including an active material, a conductive material, and a binder onto a current collector;
drying the active material layer to manufacture an electrode which is not roll-pressed;
evaluating a quality of the electrode by the method of claim 1 ; and
roll-pressing the electrode which are evaluated as a good product.
8. The method of claim 7 , wherein the slurry is applied in a loading amount of 0.005 g/cm 2 to 0.050 g/cm 2 .
9. The method of claim 7 , wherein a total heat amount required for the drying satisfies Equation 1:
Total heat amount required for the drying (kW)=(46.30 −L * value)/0.0077, Equation 1
wherein, in Equation 1, L* value is a predetermined electrode quality evaluation criterion and is 35.4 or more.
10. The method of claim 7 , wherein a total heat amount required for the drying satisfies Equation 2:
Total heat amount required for the drying (kW)=(1.09 −a * value)/2.19×10 −5 , Equation 2
wherein, in Equation 2, the a value is a predetermined electrode quality evaluation criterion and is 0.78 or more.
11. The method of claim 7 , wherein a total heat amount required for the drying satisfies Equation 3:
Total heat amount required for the drying (KW)=(13.06−whiteness value)/0.0041, Equation 3
wherein, in Equation 3, the whiteness value is a predetermined electrode quality evaluation criterion and is 7 or more.
12. The method of claim 7 , wherein the drying is carried out with a total heat amount of 1,000 kW to 1,450 kW.
13. The method of claim 7 , wherein the active material layer has a thickness of 50 μm to 500 μm.