TOPICS

“Fuel Cell System”

Overview:
The Intellectual Property (IP) High Court overturned a decision rendered by the Board of Examiners of the Japan Patent Office (JPO) to maintain the rejection of an application on the grounds that the claimed subject matter would have been easily achieved.

Main Issue:
Whether or not the “short-circuit control circuit” of the prior art is equivalent to the claimed “control device”.

Summary of Conclusion:
The IP High Court established that the claimed “control device” “is configured so as to adjust an airflow passing through a fuel cell stack…in order to provide a rehydration interval that increases a hydration level of the fuel cell stack”. The court found that the object of “to provide a rehydration interval that increases a hydration level of the fuel cell stack” is to actively increase the moisture content in a membrane electrode assembly (MEA) in order to achieve a satisfactory hydration level in the MEA, and that to “adjust an airflow passing through a fuel cell stack” means adjusting an airflow capable of causing a decrease in moisture content of the membrane and the like in order to achieve that object.
With regards to the “short-circuit control device” of the prior art which “stops a supply of fuel gas to a fuel cell…in order to prevent negative dehydration phenomena in the fuel cell stack”, the court found that to “prevent negative dehydration phenomena” refers to stopping or controlling a loss of hydration in the MEA which leads to generation of heat, that in turn causes drying of the MEA. The court considered that “stops a supply of fuel gas to a fuel cell” involves stopping a supply of fuel gas which leads to the generation of heat in the fuel cell in order to achieve that object.
The court found that the claimed “control device” and the “short-circuit control circuit” of the prior art differ in terms of whether the object is to actively increase the moisture content in the MEA or merely to stop or control a loss of hydration in the MEA or the like, and that they also differ in terms of whether they adjust airflow that could lead to a decrease in moisture on the cathode side of the fuel cell, or stop a supply of fuel gas that leads to heat generation on the anode side.
The IP High Court held that for these reasons, the JPO Board of Examiners erred in its determination that the claimed “control device” corresponds to the “short-circuit control circuit” of the prior art which was based on a finding that the object of both is “to provide a rehydration interval that increases a hydration level”.

Comments:
The claimed “control device” performs control to actively increase moisture content in the MEA, whereas the prior art performs control to suppress a decrease in moisture content in the MEA. Therefore, the control of the prior art differs from the control of the claimed control device and there is no reason that it would be performed regularly. The JPO Board of Examiners overlooked the distinction of “to suppress a decrease” and “to…increase”, which led to the incorrect determination that the claimed subject matter would have been easily achieved.