Electrochemical cell systems are provided. In some implementations, the electrochemical cell system includes a fuel cell and a fuel cartridge connected to the fuel cell. The fuel cell includes (i) a fuel cell housing having a first external surface and a first internal surface defining a first internal volume of the fuel cell housing, and (ii) a cathode, and anode, and an electrolyte disposed within the first internal volume. The fuel cartridge includes (i) a cartridge housing having a second external surface and a second internal surface defining a second internal volume of the cartridge housing, wherein the second internal volume includes a fuel; and (ii) a fuel consuming agent disposed on at least one of the first external surface and the second external surface.