Ex Parte Zhang et alDownload PDFPatent Trial and Appeal BoardDec 5, 201612939867 (P.T.A.B. Dec. 5, 2016) Copy Citation United States Patent and Trademark Office UNITED STATES DEPARTMENT OF COMMERCE United States Patent and Trademark Office Address: COMMISSIONER FOR PATENTS P.O.Box 1450 Alexandria, Virginia 22313-1450 www.uspto.gov APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO. 12/939,867 11/04/2010 Jingxin Zhang P010502-FCA-CHE 6302 65798 7590 12/05/2016 MILLER IP GROUP, PLC GENERAL MOTORS CORPORATION 42690 WOODWARD AVENUE SUITE 300 BLOOMFIELD HILLS, MI 48304 EXAMINER MCDERMOTT, HELEN M ART UNIT PAPER NUMBER 1727 MAIL DATE DELIVERY MODE 12/05/2016 PAPER Please find below and/or attached an Office communication concerning this application or proceeding. The time period for reply, if any, is set in the attached communication. PTOL-90A (Rev. 04/07) UNITED STATES PATENT AND TRADEMARK OFFICE BEFORE THE PATENT TRIAL AND APPEAL BOARD Ex parte JINGXIN ZHANG, LESLEY PAINE, AMIT NAYAR, and ROHIT MAKHARIA Appeal 2015-005492 Application 12/939,867 Technology Center 1700 Before CATHERINE Q. TIMM, CHRISTOPHER C. KENNEDY, and JEFFREY R. SNAY, Administrative Patent Judges. SNAY, Administrative Patent Judge. DECISION ON APPEAL1 Appellants2 appeal under 35 U.S.C. § 134(a) from the Examiner’s decision rejecting claims 1—5 and 13—16. We have jurisdiction under 35 U.S.C. § 6(b). We reverse. 1 We cite to the Specification (“Spec.”) filed Nov. 4, 2010, as amended Dec. 27, 2013; Final Office Action (“Final Act.”) dated May 9, 2014; Examiner’s Answer (“Ans.”); and Appellants’ Appeal Brief (“App. Br.”) and Reply Brief (“Reply Br.”). 2 Appellants identify GM Global Technology Operations LLC as the real party in interest. App. Br. 3. Appeal 2015-005492 Application 12/939,867 BACKGROUND The subject matter on appeal relates to recovering cell voltage loss in a fuel cell stack. Spec. 111. Operation of a fuel cell system results in an undesired loss of voltage and consequent reduction of stack performance due to deposition of contaminants, membrane drying, and catalyst oxide formation. Id. 19. Appellants disclose a voltage loss recovery method involving operating the stack at conditions, including reduced stack temperature, that provide excess water that flushes contaminants and reduces surface oxides. Id. ]Hf 11, 19. Claims 1 and 13 are illustrative and reproduced from the Claims Appendix of the Appeal Brief as follows: 1. A method for recovering voltage loss of fuel cells in a fuel cell stack, said method comprising: performing the following steps after or during a fuel cell system shutdown sequence: operating the fuel cell stack at a stack temperature that is less than 60°C; providing hydrogen gas to an anode side of the fuel cell stack; providing a gas flow to a cathode side of the fuel cell stack; and providing humidity to the gas flow so that the relative humidity of the gas flow is above saturation, wherein the condensation generated in the stack as a result of operating the stack at the stack temperature and liquid water provided by a saturated gas flow provide a water flow in fuel cell flow-fields that flush away contaminants deposited on electrodes in the fuel cells. 13. A method for recovering voltage loss of fuel cells in a fuel cell stack, said method comprising: performing the following steps after or during a fuel cell system shutdown sequence: 2 Appeal 2015-005492 Application 12/939,867 operating the fuel cell stack at a stack temperature that is lower than a normal stack operating temperature such that condensation will occur; providing hydrogen gas to an anode side of the fuel cell stack; providing an air flow to a cathode side of the fuel cell stack; providing humidity to the cathode air flow so that the relative humidity of the airflow is above saturation; operating the stack to provide an average cell voltage less than 650 mV; and adjusting an outlet pressure of a cathode exhaust from the fuel cell stack and flow rates of the hydrogen gas and cathode air flow so that the combination of the temperature of the stack, the average voltage of the fuel cells in the stack, the humidity level of the cathode airflow and the cathode exhaust outlet pressure provide a water flow in fuel cell flow-fields that flushes away contaminants deposited on electrodes in the fuel cells. Each of the remaining claims on appeal depends from claim 1 or claim 13. REJECTIONS3 I. Claims 1—5 and 13—16 stand rejected under 35 U.S.C. § 112, second paragraph. II. Claims 1—3, 5 and 13 stand rejected under 35 U.S.C. § 102(e) as unpatentable over Nagahara.4 III. Claims 4 and 14—16 stand rejected under 35 U.S.C. § 103(a) as unpatentable over Nagahara. 3 Final Act. 2—11; Ans. 2—10. 4 US 2011/0129751 Al,pub. Jun. 2, 2011 (“Nagahara”). 3 Appeal 2015-005492 Application 12/939,867 DISCUSSION I With regard to Rejection I, the Examiner found that “[t]he claimed ‘shutdown sequence’ has not been sufficiently defined to be able to determine when exactly in the operation of the fuel cell system the recited steps are intended to be performed.” Final Act. 3. Each of claims 1 and 13 specifies that the recited recovery steps are performed “after or during a fuel cell system shutdown sequence.” Appellants contend that a fuel cell shutdown sequence is distinct from normal operation of the fuel cell, and that “[i]t is well known that fuel cell systems do not quit abruptly when they are no longer being used as intended.” App. Br. 7. The Examiner generally concurred with the foregoing statements. See Ans. 11 (“[A] shutdown sequence as generally understood is expected to culminate with the fuel cell being in a non-operation state.”). On this record, we are persuaded that the Examiner did not articulate factual findings sufficient to support a determination that one of ordinary skill in the art would not understand the scope and meaning of either claim 1 or claim 13. Rather, these claims expressly call for the recited recovery steps to be performed after or during steps taken to shut down the fuel cell system, whatever those shutdown steps might be. While arguably broad,5 breadth alone is not indefmiteness. In re Gardner, All F.2d 786, 788 (CCPA 1970). Accordingly, we do not sustain Rejection I. 5 For example, the Examiner observed that any recovery method would occur “after a shutdown sequence, if a shutdown sequence has ever occurred previously in the lifetime of the fuel cell.” Ans. 12. 4 Appeal 2015-005492 Application 12/939,867 II In support of Rejection II, the Examiner found that Nagahara describes a fuel cell recovery operation that “includes operation of the fuel cell stack at a temperature less than a predetermined temperature, for example 40 °C.” Final Act. 4 (citing Nagahara at 1109). Appellants dispute that finding, arguing that Nagahara oppositely teaches that “if the temperature of the fuel cell reaches 40 °C the temperature is increased, i.e., recovery is not performed at 40°C.” App. Br. 10. Moreover, Appellants contend, Nagahara does not teach operating the fuel cell stack at a stack temperature of less than 60 °C (as is recited in claim 1) or at a temperature that is lower than a normal stack operating temperature (as is recited in claim 13) in the course of the described voltage recovery method. Id. In response to these arguments, the Examiner explained that the rejection is based on a reading of the claims under which the recited temperature constraint is met if Nagahara’s fuel cell stack is operated within the recited temperate range at any time, including during operation outside of the voltage recovery process. Ans. 13. We deal first with the Examiner’s stated claim interpretation. Claim 1 recites “[a] method for recovering voltage loss . . . said method comprising . . . operating the fuel cell stack at a stack temperature that is less than 60°C.” Claim 13 similarly recites that the recovery method comprises “operating the fuel cell stack at a stack temperature that is lower than a normal stack operating temperature such that condensation will occur.” Thus, these claims expressly call for the recited stack temperatures to occur as part of the recovery process. That reading is further compelled by the recitation in each of these claims that the recited stack temperature, along with other recited 5 Appeal 2015-005492 Application 12/939,867 conditions, “provide[s] a water flow in fuel cell flow-fields that flush away contaminants.” The Examiner’s interpretation—that the recited stack temperature need not be satisfied during performance of the recovery method—is contrary to the express language of the claims. Turning to Nagahara, we agree with Appellants that Nagahara fails to teach performing the described voltage loss recovery process at a temperature that would satisfy the temperature constraint recited in either claim 1 or claim 13. In Nagahara, performance recovery of a fuel cell is achieved by operating the fuel cell under conditions sufficient to oxidize adsorbed impurities. Nagahara H 5, 8. Particularly, the potential of the oxidant electrode is controlled to a desired potential based on a measured temperature of the fuel cell stack. Id. ^ 8. “If the measured temperature is equal to or more than a predetermined temperature,” the recovery procedure is performed at a predetermined potential for that temperature. Id. 143. At 40 °C, the recovery procedure is not performed. Id. 1 84. Rather, if the operating stack temperature is measured to be 60 °C or less, the temperature of the stack is increased prior to initiating the performance recovery process. Id. 84, 109. Thus, Nagahara teaches performing a recovery process at a temperature which is greater than 60 °C, and which is maintained at or higher than the measured normal operating stack temperature. The Examiner points to no other evidence that would support a finding that Nagahara teaches performing the described recovery method at less than 60 °C (claim 1) or at a temperature which is lower than a normal stack operating temperature (claim 13). Accordingly, we also do not sustain Rejection 11. 6 Appeal 2015-005492 Application 12/939,867 III The Examiner’s findings made in support of Rejection III neither address nor cure the errors identified above in connection with Rejection II. We therefore do not sustain Rejection III for the reasons set forth above. DECISION The Examiner’s decision rejecting claims 1—5 and 13—16 is reversed. REVERSED 7 Copy with citationCopy as parenthetical citation