NOVELTY - A fuel cell fuel cartridge system (10) comprises: a first storage unit (13) configured for storing liquid first fuel, and having first fluid inlet/outlet port (12a); and a second storage unit (14) configured for storing second fuel at a substantially constant pressure, and having a second fluid inlet/outlet port (12c), where second storage unit is coupled to first storage unit and is configured to pressurize the first storage unit, to permit discharge of first fuel out of first port.    USE - As a fuel cell fuel cartridge system, useful in a direct methanol fuel cell; and for purging anode or cathode of direct methanol fuel cell during operation (claimed).    ADVANTAGE - The fuel cartridge system is capable of supplying two fuels to an anode of a fuel cell body without using a pump, for direct methanol fuel cell, due to the presence of second storage unit coupled to first storage unit pressurizes first storage unit, to permit discharge of first fuel out of first port; as compared to typical direct methanol fuel cells using fuel pumps to supply fuel stored in a fuel cartridge to a fuel cell body that exhibits increased volume and noise of system and decreases energy efficiency. The fuel cartridge system further avoids the other problems associated with the prior art fuel cells such as accumulation of carbon dioxide at anode after extended operating time, which prevents supply of fuel, and leads to lack of fuel; and water flooding at cathode that reduces fuel supply; which then causes deterioration of anode and cathode, by allowing for purging of anode or cathode during operation of the fuel cell. By carrying out anode purging process, clogging phenomenon of fuel flow path caused by accumulation of carbon dioxide can be reduced and/or prevented, by forcibly discharging carbon dioxide. By carrying out the cathode purging process, water flooding at the cathode can be reduced and/or prevented by removing moisture in cathode flow path of fuel cell body and gas diffusion layer of cathode. Thus fuel cartridge prevents deterioration in performance of fuel cell and provides stable operating conditions of fuel system for extended time. The elimination of a fuel pump, results in small and light-weight fuel system and a reduced noise level, as well as an improved energy density compared with fuel cells using only methanol as the fuel; provide improved notice to the user for fuel cartridge exchange; provide a high-efficiency direct methanol fuel cell having a novel structure comprising fuel cartridge storing two fuels; and provide high-reliability direct methanol fuel cell capable of easily purging anode and cathode during operation of fuel system.    DETAILED DESCRIPTION - A fuel cell fuel cartridge system (10) comprises: a first storage unit (13) configured for storing liquid first fuel, and having first fluid inlet/outlet port (12a); and a second storage unit (14) configured for storing second fuel at a substantially constant pressure, and having a second fluid inlet/outlet port (12c), where second storage unit is coupled to first storage unit and is configured to pressurize the first storage unit, to permit discharge of first fuel out of first port. The system comprises first storage unit comprising first container, second storage unit comprising second container, and fuel cartridge further comprising first coupling unit fluidly connected to first container and second coupling unit fluidly connected to second container, which are enageable to each other, such that when engaged, open a port in at least one of the unit, to fluidly connect first container to second container; or a single container (11) comprising first storage unit and second storage unit, a barrier rib dividing the unit, and subpipe fluidly coupling second storage unit to first storage unit, and further a subvalve coupled to subpipe, for controlling pressure of second fuel flowing through subpipe. The fuel cartridge system further comprises a controller to permit fuel cartridge to supply first fuel from the first storage unit and second fuel from second storage unit either simultaneously or separately; and a temperature maintenance unit coupled to second storage unit, to maintain temperature of second storage unit within a predetermined range that is a heating apparatus for heating second storage unit. INDEPENDENT CLAIMS are included for the following:    (1) a direct methanol fuel cell comprising: the fuel cartridge system; a fuel cell body configured for generating electric energy by electrochemically reacting oxidizing agent supplied to cathode with first fuel and/or second fuel supplied from fuel cartridge an anode; and further a recycler comprising discharging unit fluidly coupled with fuel cartridge, such that recycler is fluidly coupled to anode and cathode outlets, and is configured for recycling unreacted fuel and water from fuel cell body to fuel cartridge;    (2) method for purging anode of direct methanol fuel cell during operation of direct methanol fuel cell, involving: closing first fluid inlet/outlet port of fuel cartridge; closing cathode outlet of fuel cell body; and opening second fluid inlet/outlet port, to discharge second fuel, to purge anode of direct methanol fuel cell for 10-30 seconds and returning the direct methanol fuel cell to normal mode; and    (3) method for purging cathode of direct methanol fuel cell during operation of direct methanol fuel cell, involving: closing first fluid inlet/outlet port of the fuel cartridge; closing discharging unit of the recycler; closing cathode outlet of fuel cell body for 10-30 seconds; opening cathode outlet, to purge cathode of direct methanol fuel cell; and returning direct methanol fuel cell to a normal operation mode.    ORGANIC CHEMISTRY - The first fuel comprises methanol and second fuel comprises dimethyl ether.    DESCRIPTION OF DRAWING(S) - The figure shows direct methanol fuel cell comprising the fuel cartridge.    Fuel cartridge (11) Single container (10)    First fluid inlet/outlet port (12a)    Second fluid inlet/outlet port (12c)    First storage unit (13)    Second storage unit (14)