A fuel cell stack includes a plurality of cell groups and a controller wherein each cell group comprises a plurality of fuel cells and a group sensor which measures one or more electrical characteristics of the respective cell group. The controller comprises one or more processors and memory and is communicatively coupled to each group sensor. The one or more processors execute machine readable instructions to compare a measured electrical characteristic of each cell group to one or more thresholds stored in memory, and indicate the need for diagnostics of the fuel cell stack when the comparison indicates a non-systemic event.

Provided are a metal plate configured such that sufficient strength and performance are ensured and the workability and cost of mass production are improved, and an electrochemical element and the like including the metal plate. A metal plate 1 includes a thick portion 110, and a thin portion 120 that is thinner than the thick portion 110. The thin portion 120 is provided with a penetration space 1c passing through the thin portion 120 in the thickness direction.

When a time point of occurrence of a stop state of a fuel cell system is predicted during traveling, a drying state control that causes a fuel cell stack to transition to a dry state is started a predetermined time (a required drying time) before the predicted time point of occurrence of the stop state.

Disclosed are an ionic conductivity measurement device and method for a fuel cell, which enable accurate measurement of ionic conductivity of a membrane electrode assembly for a fuel cell under various conditions. The ionic conductivity measurement device includes a main body frame, a clamp handle mounted to the upper portion of the main body frame, a lift shaft connected to the clamp handle so as to be movable upwards and downwards, a motion jig mounted to the main body frame so as to be movable upwards and downwards and including an upper support frame connected to the lower end of the lift shaft and a specimen support frame connected to the upper support frame, a lower support frame mounted to the lower end portion of the main body frame, an upper probe pin mounted to the upper support frame, and a lower probe pin mounted to the lower support frame.

Provided are a metal plate configured such that sufficient strength and performance are ensured and the workability and cost of mass production are improved, and an electrochemical element and the like including the metal plate. A metal plate 1 includes a thick portion 110, and a thin portion 120 that is thinner than the thick portion 110. The thin portion 120 is provided with a penetration space 1c passing through the thin portion 120 in the thickness direction.

In a case where each of the temperature, the impedance, and the output current of a fuel cell stack falls within a predetermined range, the output voltage of the fuel cell stack is measured, and the measured output voltage is compared with a reference value to thereby determine the degree of degradation of the fuel cell stack.

Disclosed are a method and apparatus for subzero start-up of a fuel cell. The method for the subzero start-up of the fuel cell includes: introducing a gas containing hydrogen having a mass percentage of 5% to 100% to a hydrogen electrode and an air electrode of the fuel cell (2) under a condition of minus 50° C. to 0° C.; applying a current or a voltage to the fuel cell (2), and utilizing ohmic heat generation, reaction heat, and concentration overpotential heat generation of the fuel cell (2) to raise the fuel cell (2) to a required temperature or to cause the fuel cell (2) to reach to a set time, so as to implement the subzero start-up of the fuel cell.

To provide a fuel cell system capable of evaluating degradation of an electrolyte membrane by quantifying metal ions involved in degradation of an electrolyte membrane instead of evaluating degradation of an electrolyte membrane itself. A fuel cell system comprising a fuel cell, a fuel gas system for supplying fuel gas to an anode of the fuel cell, an oxidant gas system for supplying oxidant gas to a cathode of the fuel cell, a voltage detector for detecting a voltage of the fuel cell, and a controller.

A fuel cell system includes: a fuel cell stack; a first cooling medium circuit through which a cooling medium for cooling the fuel cell stack flows; an ion exchanger that removes ions in the cooling medium; a second cooling medium circuit in which the average ion concentration of the cooling medium is lower than that of the cooling medium in the first cooling medium circuit; a switching valve that switches between a flow state and a low flow state; a pump configured to cause the cooling medium in the second cooling medium circuit to flow into the first cooling medium circuit; and a control unit that, when a stop period of the fuel cell system is longer than a reference period, drives the pump with the switching valve switched to the flow state after the instruction to start the fuel cell system is input.

Disclosed are a method and apparatus for subzero start-up of a fuel cell. The method for the subzero start-up of the fuel cell includes: introducing a gas containing hydrogen having a mass percentage of 5% to 100% to a hydrogen electrode and an air electrode of the fuel cell (2) under a condition of minus 50° C. to 0° C.; applying a current or a voltage to the fuel cell (2), and utilizing ohmic heat generation, reaction heat, and concentration overpotential heat generation of the fuel cell (2) to raise the fuel cell (2) to a required temperature or to cause the fuel cell (2) to reach to a set time, so as to implement the subzero start-up of the fuel cell.