NOVELTY - An electroconductive ink composition contains electroconductive particles and organic-type vehicle including heat-hardenable resin composition, hardening agent and solvent. The heat-hardenable resin composition contains epoxy resin composition (A) which is solid at room temperature and epoxy resin composition (B) which is liquid at room temperature. The mass ratio of epoxy resin composition (A) and epoxy resin composition (B) is 50-85:15-50. The total content of epoxy resin composition is 100 %mass.    USE - Electroconductive ink composition is used for forming collector electrode of photovoltaic cell and lead wire, of solar cell module (all claimed).    ADVANTAGE - The collector electrode of photovoltaic cell has excellent reliability and heat resistance. Since lead wire formed using electroconductive ink composition has low resistance, the solar cell module comprising lead wire has excellent photoelectric conversion efficiency.    DETAILED DESCRIPTION - An electroconductive ink composition contains electroconductive particles and organic-type vehicle including heat-hardenable resin composition, hardening agent and solvent. The heat-hardenable resin composition contains epoxy resin composition (A) which is solid at room temperature and epoxy resin composition (B) which is liquid at room temperature. The mass ratio of epoxy resin composition (A) and epoxy resin composition (B) is 50-85:15-50. The total content of epoxy resin composition is 100 %mass. The mass ratio of heat-hardenable resin composition and electroconductive particles are 2-15:75-95. The epoxy resin composition (A) has melt viscosity of 0.5 Pa.second or less at 150 degrees C. The epoxy resin composition (B) has melt viscosity of 10 Pa.second or less. INDEPENDENT CLAIMS are included for the following:    (1) photovoltaic cell, which has collector electrode formed using electroconductive ink composition; and    (2) solar cell module.    DESCRIPTION OF DRAWING(S) - The drawing shows cross sectional view of photovoltaic cell. (Drawing includes non-English language text)    N-type single crystal silicon substrate (11)    Amorphous-silicon layers (12,16)    Transparent electrodes (13,17)    Collector electrode (14)