Humidifier

The present invention provides a humidifier for fuel cells having a housing, a metal heat-exchange plate, a water-trapping reservoir, water permeable stuffing material and water absorbable and permeable stuffing material; the heat-exchange plate, disposed in the housing, divides the housing into a first gas passage and a second gas passage, the water permeable stuffing material is disposed in the first gas passage, and the water saturation aperture and the water-trapping reservoir are disposed underneath the heat-exchange plate with the water-trapping reservoir having the water absorbable and permeable material disposed therein, thus the dry and cold oxygen/air shall be channeled to the first gas passage within the housing of the humidifier and conveyed to the oxygen/air inlet of the fuel cell, and high-temperature and high-moisture exhaust gas discharged from the fuel cell is introduced to the second gas passage within the housing of the humidifier, such that water and heat of the exhaust gas in the second gas passage are recycled by the heat-exchange plate and conveyed to the first gas passage, and the humidification effect is achieved so as to effectively improve the electricity-generating efficiency of the fuel cell.