Patent ID: 8158293
Filing Date: 2012-04-17
Classification: B60L,H01M,Y02E,Y02T

Abstract:
1. A fuel cell system, comprising: a fuel cell; a secondary battery connected with the fuel cell; an oxidizing gas supplier configured to supply an oxidizing gas to the fuel cell to be utilized for power generation by the fuel cell and operated by electric power supplied from the secondary battery; a gas supply flow regulator configured to regulate a gas supply flow rate, wherein the gas supply flow rate is amount of the oxidizing gas supplied by the oxidizing gas supplier; an oxidizing gas supply path arranged to connect the oxidizing gas supplier with the fuel cell; a cathode off-gas exhaust path arranged to discharge cathode off-gas from the fuel cell; a bypass flow path arranged to connect the oxidizing gas supply path with the cathode off-gas exhaust path; a flow regulator configured to control a flow ratio of a fuel cell-requiring gas flow rate to a bypass flow rate in a total flow of the oxidizing gas supplied from the oxidizing gas supplier, wherein the a flow ratio of a fuel cell-requiring gas flow rate is a flow rate of the oxidizing gas flowing through the oxidizing gas supply path to the fuel cell, wherein the bypass flow rate is a flow rate of the oxidizing gas flowing through the oxidizing gas supply path to the bypass flow path; an available power output acquirer configured to obtain an available amount of power output from the secondary battery; and an operation controller configured to set a target current value and a target voltage value of the fuel cell based on a required amount of power output and a required amount of heat for the fuel cell, and control the flow regulator to regulate the fuel cell-requiring gas flow rate and the bypass flow rate, so as to achieve low-efficiency operation of the fuel cell, where the fuel cell is operated at an operating point of a lower power generation efficiency than a power generation efficiency on a current-voltage characteristic curve of the fuel cell, wherein the gas supply flow regulator regulates the gas supply flow rate to cause the oxidizing gas supplier to supply an excess gas flow rate, which is set to be greater than a target fuel gas-requiring gas flow rate, wherein the target fuel gas-requiring gas flow rate is the fuel cell-requiring gas flow rate to be supplied to the fuel cell in order to achieve the target current value, when the available amount of power output from the secondary battery is less than a minimum amount of electric power required for the oxidizing gas supplier to increase the gas supply flow rate from 0 to a preset gas flow rate within a preset time period, and the operation controller controls the flow regulator to make the bypass flow rate equal to a difference gas flow rate between the excess gas flow rate and the target fuel cell-requiring gas flow rate.