US 10,256,654 B2Granted

Fuel cell system

AssigneeToyota Jidosha Kabushiki Kaisha

InventorsTakao Watanabe, Akihiro Kamiya, Kenji Umayahara

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Abstract

On a start of a fuel cell system, (i) when the temperature of a high-voltage secondary battery obtained from a temperature sensor is higher than a predetermined reference value, a controller of the fuel cell system is configured to set an output voltage on a step-down side of a DC-DC converter to a higher voltage than a voltage of a low-voltage secondary battery and subsequently start an FC auxiliary machine using electric power from the high-voltage secondary battery. (ii) When the temperature of the high-voltage secondary battery obtained from the temperature sensor is equal to or lower than the predetermined reference value, on the other hand, the controller of the fuel cell system is configured to set the output voltage on the step-down side of the DC-DC converter to a lower voltage than the voltage of the low-voltage secondary battery and subsequently start the FC auxiliary machine using the electric power from the high-voltage secondary battery.

Claims20

Dependent claims

A fuel cell system, comprising:

a fuel cell;
an FC auxiliary machine used to supply fuel or gas to the fuel cell to cause the fuel cell to generate electric power;
a high-voltage secondary battery configured to supply electric power to the FC auxiliary machine;
a low-voltage secondary battery configured to have a lower output voltage than a voltage of the high-voltage secondary battery;
a DC-DC converter configured to step down the voltage of the high-voltage secondary battery and supply the stepped-down voltage to the low-voltage secondary battery;
a loading device connected between the low-voltage secondary battery and the DC-DC converter;
a temperature sensor configured to measure temperature of the high-voltage secondary battery;
and
a controller used to start the fuel cell system, wherein the controller is configured to perform
(i) a first operation to set an output voltage on a step-down side of the DC-DC converter to a higher voltage than the voltage of the low-voltage secondary battery and subsequently start the FC auxiliary machine using the electric power from the high-voltage secondary battery, when the temperature of the high-voltage secondary battery obtained from the temperature sensor is higher than a predetermined reference value;
and
(ii) a second operation to set the output voltage on the step-down side of the DC-DC converter to a lower voltage than the voltage of the low-voltage secondary battery and subsequently start the FC auxiliary machine using the electric power from the high-voltage secondary battery, when the temperature of the high-voltage secondary battery obtained from the temperature sensor is equal to or lower than the predetermined reference value.

9 more elements

A fuel cell system, comprising:

a fuel cell;
an FC auxiliary machine used to supply fuel or gas to the fuel cell to cause the fuel cell to generate electric power;
a high-voltage secondary battery configured to supply electric power to the FC auxiliary machine;
a low-voltage secondary battery configured to have a lower output voltage than a voltage of the high-voltage secondary battery;
a DC-DC converter configured to step down the voltage of the high-voltage secondary battery and supply the stepped-down voltage to the low-voltage secondary battery;
a loading device connected between the low-voltage secondary battery and the DC-DC converter;
a temperature sensor configured to measure temperature of the high-voltage secondary battery;
and
a controller used to start the fuel cell system, wherein the controller is configured to perform
(i) a first operation to set an output voltage on a step-down side of the DC-DC converter to a higher voltage than the voltage of the low-voltage secondary battery and subsequently start the FC auxiliary machine using the electric power from the high-voltage secondary battery, when the temperature of the high-voltage secondary battery obtained from the temperature sensor is higher than a predetermined reference value;
and
(ii) a second operation to keep operation of the DC-DC converter at stop or to separate the DC-DC converter from the low-voltage secondary battery by means of a relay and subsequently start the FC auxiliary machine using the electric power from the high-voltage secondary battery, when the temperature of the high-voltage secondary battery obtained from the temperature sensor is equal to or lower than the predetermined reference value.

9 more elements

Dependencies are inferred from the claim text.