TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Component: The humidifier (10) comprises stacked humidification units, each including a first plate (110) having first grooved surface communicating with the fuel cell module (20) to introduce the first airflow into the fuel cell module; a second plate (120) having second grooved surface communicating with the fuel cell module to drain the second airflow to the atmosphere, where the second plate is stacked on the first plate with the second grooved surface facing to the first grooved surface; an intermediate layer (130) disposed between the first plate and the second plate to separate the gases in the first grooved surface and the second grooved surface and transfer the produced water from the second airflow in the second grooved surface to the introduced air in the first grooved surface. Each intermediate layer comprises a water-permeating membrane; a water-absorbent membrane attached to the water-permeating membrane near the second plate to absorb the water in the second airflow. The water absorbed by the water-absorbent membrane is delivered to the introduced air in the first grooved surface by the water-permeating membrane. The fuel cell assembly further comprises a top plate with an air inlet communicating with the first and third holes of each humidification unit; and a cooler, providing refrigerant to cool the fuel cell module. The fuel cell module comprises a first electrode; a second electrode; and stacked fuel cell units disposed between the first and second electrodes. Each fuel cell unit comprises an anode bipolar plate (210) having third grooved surface communicating with the hydrogen source to introduce hydrogen; a cathode bipolar plate (220) having fourth grooved surface communicating with the humidifier to introduce the first airflow and remove produced water, forming the second airflow, where the fourth grooved surface faces to the third grooved surface; and a membrane electrode assembly (230) having an anode gas diffusion layer, a proton exchange membrane, and a cathode gas-diffusion layer sequentially disposed between the anode bipolar plate and the cathode bipolar plate to chemically combine hydrogen and oxygen, producing electricity.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Material: The refrigerant is air or water.