Patent ID: 9209469
Filing Date: 2015-12-08
Classification: C01B,H01M,Y02E

Abstract:
1. A solid oxide fuel cell system, comprising: a cell stack including an array of multiple fuel cell units; a reformer configured to reform fuel gas and supply the reformed fuel gas to the fuel cell units; a combustion portion configured to burn an unused surplus of the reformed fuel gas having passed through the fuel cell units and produce high temperature exhaust gas which is used to heat the reformer and the cell stack; a temperature detector configured to detect a temperature of the cell stack and a temperature of the reformer; a module housing chamber shaped to house the cell stack and the reformer; a heat storage disposed around the module housing chamber; and a controller programmed to thermally prepare the fuel cell system for generation of electricity through sequentially performed startup operations comprising a steam reforming (SR) reaction operation, wherein the controller is programmed to supply fuel gas, oxidant gas, and steam at controlled supply rates to the reformer during the startup operations and advance the startup operations in sequence from one operation to a next operation upon a determination by the controller that the detected cell stack temperature and the detected reformer temperature exceed a set of cell stack transition temperature and reformer transition temperature, respectively, which are predetermined to advance the startup operations from the one operation to the next operation, and wherein the controller is further programmed to: (a) at a transition from the one startup operation to the next startup operation, determine whether the detected reformer temperature exceeds a first threshold temperature of multiple predetermined threshold temperatures, wherein the first threshold temperature is higher than the reformer transition temperature; (b) upon a determination by the controller that the detected reformer temperature exceeds the first threshold temperature, start an overheat preventive operation at a beginning of the next startup operation, wherein during the overheat preventive operation, the controller is programmed to supply the fuel gas to the reformer at a fuel supply rate decreasing over time; and (c) end the overheat preventive operation at an end time at which the controller is programmed to stop the fuel supply rate from decreasing, wherein the end time is determined adaptively to the detected reformer temperature.