Method for determining good-quality product of electrode ink

A method of determining a good quality of an electrode ink configured to include a plurality of catalyst supports and a plurality of ionomers, and configured to form a catalyst layer of a fuel cell,

• wherein, in an inner portion of the electrode ink, by adsorption of the ionomers around the catalyst supports, primary aggregate that does not aggregate with others of the catalyst supports is formed, while on the other hand, by aggregation of the catalyst supports themselves without the ionomers around the catalyst supports, secondary aggregate is formed,
• the method of determining the good quality of the electrode ink comprising:
• detecting elastic modulus of the electrode ink;
• estimating a state of the primary aggregate and the secondary aggregate within the electrode ink based on the detected elastic modulus;
• and
• as the primary aggregate becomes more plentifully contained relative to the secondary aggregate, the more it is determined that the electrode ink is a good-quality product.