Patent ID: 11876261
Assignee: PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO., LTD.
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H  Y | IPC H

Claim 0:
1. A fuel cell system comprising:
a fuel cell configured to generate electricity using a fuel gas and an oxidant gas;
a fuel gas supply path through which a fuel gas to be supplied to an anode of the fuel cell flows;
a recycle gas path through which an anode off-gas emitted from the anode of the fuel cell is returned to the fuel gas supply path;
a water reservoir that holds water separated from the anode off-gas flowing through the recycle gas path;
a drainage path through which water stored in the water reservoir is drained;
a valve provided on the drainage path; and
a controller that includes a processor and a storage that stores a program,
wherein the program, when executed by the processor, causes the controller to, when the fuel cell is operating at a rated output:
open the valve in response to a request for drainage of the anode off-gas,
determine, without using a water volume sensor, a length of time for which the valve continues to be opened for draining the water stores in the water reservoir,
(i) by using an integrated value of the flow rate of the anode off-gas obtained from a history of a flow rate of the anode off-gas, the history comprising time-dependent changes in the flow rate of the anode off-gas during the valve being closed, and
(ii) by using any one of a history of an amount of electricity generated by the fuel cell, a history of a temperature of the anode off-gas, a history of an amount of water vapor that is contained in the anode off-gas, and a pressure of the anode off-gas at a time of opening of the valve, and
close the valve when a time from opening the valve reaches the determined length of time.