In this report we propose a state space model of a direct methanol fuel cell. This dynamical model allows analysis and optimisation of the fuel cell in a control-theoretical framework, for instance to improve the overall dynamics of the fuel cell or to reject environmental disturbances. The model is particularly well suited to synthesise controllers, which are necessary to ensure stable, robust and efficient operation of a fuel cell. To yield a state space model of the direct methanol fuel cell, a system of nonlinear partial differential equations is transformed into a system of ordinary initial value problems by Laplace transforms, approximation in function spaces and the method of weighted residuals.