NOVELTY - Fuel cell system comprises fuel cell stack supplied with liquid methanol/water fuel mixture on anode side and air on cathode side; methanol storage tank; water storage tank; circulation pump for circulating liquid methanol/water fuel mixture from methanol and water storage tanks through fuel cell stack and the partially depleted methanol/water mixture to a storage tank; and freezing point depressant storage tank, which supplies the fuel cell stack with freezing point depressant during shut-down; or inert gas storage tank, which flushes the fuel cell stack with inert gas during shut-down.    USE - Fuel cell i.e. DMFC system (claimed).    ADVANTAGE - Degradation of DMFC components at temperatures below room temperature and especially below the freezing point of fuel/water mixtures is reduced. The freezing point depressant is compatible with fuel cell material components and does not deleteriously affect electrode processes of the fuel cell system. The system realizes fuel cell deactivation processes that leave the DMFC in a non-reactive state during dormant periods and provides for carefully controlled re-activation of the dormant cell without adding complexity and without lowering efficiency of the fuel cell. Undesired side reactions at the cathode are limited by replacement of residual oxygen in the fuel cell before shutting down with inert gas. Inert gases nitrogen and carbon dioxide are non-reactive with alcohol and catalyst; and any deleterious reaction will not occur at the cathode during dormancy when oxygen is replaced by any of the inactive gases singly or in a mixture. During start-up of the DMFC, any freezing point depressants can be consumed by the power generating process and not by unwanted side reaction upon restarting, where inert flushing gas is steadily replaced by air and the DMFC is subjected to small electrical load. Heat is generated during the start-up of the DMFC. Since the power generating reaction involving the higher alcohols is slower than that of methanol, heating occurs more slowly thus giving time for more uniform heat distribution through the entire DMFC, thus, reducing the risk of forming hot spots with ensuing damage. By-products of the higher alcohols such as aldehydes and ketones can be removed by the air stream passing the cathode during start-up. These products may be further finally oxidized to the corresponding water-soluble acids and removed as entrained aqueous solutions. The amounts of these by-products are limited and have no influence on the DMFC performance. The use of glycol containing 2 hydroxy-groups as the freezing point depressants produces residual oxidation products having a lighter mass, and which are even more volatile, thus enhancing removal in the air stream. On restarting, a small electrical load is applied to the fuel cell to initiate the power generating reaction between air and alcohol or glycol and heating of the fuel cell.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for frost protecting a fuel cell system during shut-down comprising releasing the electrical load on a direct methanol fuel cell (DMFC) and bringing the DMFC to an open circuit state; interrupting the feeding of methanol fuel to liquid fuel compartment of DMFC; and replacing any methanol in the DMFC with freezing point depressant.    DESCRIPTION OF DRAWING(S) - The drawing is a schematic diagram of fuel cell system with freezing point depressant tank.