Ex Parte Noetzel et al

Board of Patent Appeals and Interferences

Jan 30, 2009

11266987 (B.P.A.I. Jan. 30, 2009)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________

Ex parte JOHN G. NOETZEL, KARL J. HALTINER, JR.,
and KAUSHIK RAJASHEKARA
____________

Appeal 2008-5923
Application 11/266,987
Technology Center 1700
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Decided:1 January 30, 2009
____________

Before ADRIENE LEPIANE HANLON, TERRY J. OWENS, and
LINDA M. GAUDETTE, Administrative Patent Judges.

OWENS, Administrative Patent Judge.

DECISION ON APPEAL
STATEMENT OF THE CASE
The Appellants appeal under 35 U.S.C. § 134(a) from the Examiner’s
rejection of claims 1-5, 7-11, 18, and 21, which are all of the pending claims.
We have jurisdiction under 35 U.S.C. § 6(b).
The Invention

1 The two-month time period for filing an appeal or commencing a civil
action, as recited in 37 C.F.R. § 1.304, begins to run from the decided date
shown on this page of the decision. The time period does not run from the
Mail Date (paper delivery) or Notification Date (electronic delivery).
Appeal 2008-5923
Application 11/266,987

The Appellants claim a fuel cell system. Claim 1 is illustrative:

1. A fuel cell system, comprising:
a fuel cell unit having a fuel cell stack, said fuel cell unit
producing a fuel cell voltage and a fuel cell current;
a power conditioner electrically connected to said fuel cell unit,
said power conditioner including a power switching device, said
power switching device selectively connecting and disconnecting said
fuel cell voltage to at least one load dependent at least in part upon an
operating temperature of said fuel cell stack to thereby produce an
output voltage, wherein said power switching device comprises one of
an integrated gate bipolar transistor or a power metal oxide
semiconductor field effect transistor.
The References
Fuglevand 6,096,449 Aug. 1, 2000
Piovaccari 6,229,289 B1 May 8, 2001
Treece 2002/0163819 A1 Nov. 7, 2002
Schmidt 2003/0091882 A1 May 15, 2003
The Rejections
The claims stand rejected as follows: claims 1-5 and 7-11 under
35 U.S.C. § 102(e) over Treece; claims 1-5, 7-11 and 18 under
35 U.S.C. § 103 over Fuglevand in view of Schmidt and Piovaccari; and
claim 21 under 35 U.S.C. § 103 over Fuglevand in view of Schmidt.
OPINION
We reverse the rejection under 35 U.S.C. § 102(e) and affirm the
rejections under 35 U.S.C. § 103.
Rejection under 35 U.S.C. § 102(e)
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Appeal 2008-5923
Application 11/266,987

“Anticipation requires that every limitation of the claim in issue be
disclosed, either expressly or under principles of inherency, in a single prior
art reference.” Corning Glass Works v. Sumitomo Elec. U.S.A., Inc., 868
F.2d 1251, 1255-56 (Fed. Cir. 1989).

Issue
Have the Appellants shown reversible error in the Examiner’s
determination that Treece discloses, expressly or inherently, a power
switching device selectively connecting and disconnecting a fuel cell voltage
to at least one load dependent at least in part upon an operating temperature
of a fuel cell stack to thereby produce an output voltage?
Findings of Fact
Treece discloses a turbine/fuel cell hybrid comprising a power
controller (310, which is an embodiment of power controller 201), that
varies the amount of fuel provided to a fuel cell module (950) (¶¶ 0059,
0220; Fig. 21A). The fuel cell module is capable of operating at a variety of
operating temperatures depending on the type of fuel cell used (¶ 0023).
The power controller includes three decoupled or independent control loops
for controlling rotary speed, temperature and DC bus voltage (¶¶ 0053-
0054).
Analysis
The Appellants argue that none of Treece’s three independent control
loops relates to connecting and disconnecting fuel cell voltage to at least one
load dependent at least in part upon an operating temperature of the fuel cell
stack (Br. 8-10).
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Appeal 2008-5923
Application 11/266,987

The Examiner argues that “it is quite clear in paragraphs [0055]
and [0058] that the power controller is relying on the temperature as
controlled by the temperature control loop to determine when to apply or
remove the power from the DC bus (i.e. selectively connecting or
disconnecting the voltage)” (Ans. 6), and that “the ‘Power Controller’
[¶ 0054] comprises three control loops which includes the temperature
control loop”. See id.
Treece’s paragraph 0055 discloses that the temperature control loop in
paragraph 0054 regulates a temperature related to the desired operating
temperature of the primary combustor (50), not the fuel cell module (950,
Fig. 21A). Treece’s paragraph 0058 discloses, in reference to Figure 2, that
power controller 201 regulates temperature to a set point. In Figure 2,
temperature controller 228C sends a signal to fuel controller 50P and
receives a signal from turbine 70. There are no signals sent to or received
from a fuel cell module. Treece discloses in paragraph 0058 that the power
controller applies power to or receives power from DC bus 204, but Treece
does not disclose that the power controller does so based at least in part upon
an operating temperature of a fuel cell stack.
Conclusion of Law
The Appellants have shown reversible error in the Examiner’s
determination that Treece discloses, expressly or inherently, a power
switching device selectively connecting and disconnecting a fuel cell voltage
to at least one load dependent at least in part upon an operating temperature
of a fuel cell stack to thereby produce an output voltage.
Rejections under 35 U.S.C. § 103
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Appeal 2008-5923
Application 11/266,987

The Appellants argue only the independent claims, i.e., claims 1, 7,
18, and 21 (Br. 12-17). We therefore limit our discussion to those claims.
The dependent claims stand or fall with the independent claim from which
they depend. See 37 C.F.R. § 41.37(c)(1)(vii) (2007).
Claims 1, 7 and 21
Issue
Have the Appellants shown reversible error in the Examiner’s
determination that the applied references would have rendered prima facie
obvious, to one of ordinary skill in the art, a power switching device
selectively connecting and disconnecting a fuel cell voltage to at least one
load dependent at least in part upon an operating temperature of a fuel cell
stack to thereby produce an output voltage?
Findings of Fact
Schmidt discloses a fuel cell power system (10) comprising a
controller (102) that “monitors operational parameters of fuel cell power
system 10, such as voltages, currents and temperatures to determine an
appropriate pulse-width modulation duty cycle” (¶ 0095), and “is configured
to monitor other operational parameters [other than voltages and currents] of
fuel cell power system 10, such as temperature within housing 12 or
temperature within individual fuel cell cartridges 14 using temperature
sensors (see, e.g., sensor 55 in FIG. 2)” (¶ 0082). Schmidt teaches that
“[c]ontroller 102 is configured to vary the duty cycle of the control signals to
provide a desired operation (¶ 0095). 2

2 A discussion of Fuglevand and Piovaccari is not necessary to our resolution
of this issue.
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Appeal 2008-5923
Application 11/266,987

Analysis
The Examiner relies upon Schmidt for a suggestion of a power
switching device selectively connecting and disconnecting a fuel cell voltage
to at least one load dependent at least in part upon an operating temperature
of a fuel cell stack to thereby produce an output voltage (Ans. 4).
The Appellants argue that the “statement which is provided in
paragraph [0095] generally states that the controller 102 monitors the
temperatures in the fuel cell power system (10), but does not identify what is
monitored for temperature within the fuel cell power system (10)” (Br. 12),
and that “[w]hile paragraph [0082] of the Schmidt reference discusses
monitoring the temperature of the individual fuel cell cartridges (14), this
statement is directed toward using the sensors (55), which monitor the
temperature of the air going into the individual fuel cell cartridges (14) and
not the temperature of the individual fuel cell cartridges (14) themselves”
(Br. 13).
Schmidt discloses in paragraph 0082 that operational parameters other
than voltages and currents “such as temperature within housing 12 or
temperature within individual fuel cell cartridges 14” are monitored “using
temperature sensors”, and then Schmidt tells the reader to “see, e.g., sensor
55 in FIG. 2”. Thus, Schmidt appears to be stating either that temperature
sensor 55 in Figure 2 monitors not only the plenum 51 temperature (¶ 0061)
but also the temperature within individual fuel cell cartridges 14, or that
sensor 55, used to monitor the plenum 51 temperature, is an example of
temperature sensors that can be used to monitor temperatures such as those
within housing 12 and fuel cell cartridges 14. Schmidt, therefore, would
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Appeal 2008-5923
Application 11/266,987

have led one of ordinary skill in the art, through no more than ordinary
creativity, to use temperature sensor 55 or one like it to monitor the
temperatures within individual fuel cell cartridges 14. See KSR Int’l. Co. v.
Teleflex Inc., 127 S. Ct. 1727, 1741 (2007) (In making an obviousness
determination one “can take account of the inferences and creative steps that
a person of ordinary skill in the art would employ.”). Each of those
temperatures would be an operating temperature of the fuel cell stack as
required by the Appellants’ claims 1, 7, and 21.
Conclusion of Law
The Appellants have not shown reversible error in the Examiner’s
determination that the applied references would have rendered prima facie
obvious, to one of ordinary skill in the art, a power switching device
selectively connecting and disconnecting a fuel cell voltage to at least one
load dependent at least in part upon an operating temperature of a fuel cell
stack to thereby produce an output voltage.
Claim 18
Issue
Have the Appellants shown reversible error in the Examiner’s
determination that the applied references would have rendered prima facie
obvious, to one of ordinary skill in the art, a fuel cell system comprising a
power switching device that is in a linear mode of operation when the fuel
cell temperature has reached an operating temperature and when the
difference between the output voltage and the fuel cell voltage is less than
3.0 volts, and is in a pulse-width modulated mode of operation when the fuel
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Appeal 2008-5923
Application 11/266,987

cell temperature has reached an operating temperature and the difference
between the output voltage and the fuel cell voltage is at least 3.0 volts?
Findings of Fact
Piovaccari discloses “a method and apparatus for transitioning a
power converter between a switched mode of operation and a linear
regulator mode of operation in a single power converter” (col. 1, ll. 6-9).3
Piovaccari discloses (col. 3, ll. 33-46):
The switch-mode regulator has the advantage of operating at a higher
(compared to the linear regulator) efficiency level when the
difference[s] between the input and output voltages are large, but
cannot operate correctly at low differential voltages. The linear
regulator has the advantage of operating at a lower differential
voltage, but is not as efficient when operating at high differential
voltages.
Because a switch-mode power converter can operate more
efficiently at a higher input-output differential voltage, and a linear
regulator can operate more efficiently at a smaller input-output
differential voltage, providing a single power converter that includes
both modes allows for efficient power conversion for both large and
small voltage differentials.

Piovaccari discloses that a linear regulator “can operate at a smaller input-
output differential voltage, often less than 100 mV, depending on the rated
output current” (col. 3, ll. 17-20).4
Analysis
The Appellants argue that the applied references do “not teach or
suggest a fuel cell system including a power switching device that

3 Piovaccari’s disclosed switch-mode regulator is a pulse-width modulated
controller (PWM 104; col. 4, ll. 54-56; col. 5, ll. 8-12).
4 A discussion of Fuglevand is not necessary to our resolution of this issue.
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Appeal 2008-5923
Application 11/266,987

selectively connects and disconnects fuel cell voltage to at least one load
dependent at least in part upon an operating temperature of the fuel cell stack
to thereby produce an output voltage as recited in claim 18” (Br. 15).
That argument is not well taken because the Appellants are arguing a
limitation that is not in claim 18. See In re Self, 671 F.2d 1344, 1348
(CCPA 1982). Claim 18 does not recite “dependent at least in part upon an
operating temperature of the fuel cell stack” but, rather, recites “dependent at
least in part upon said fuel cell temperature”. Even Schmidt’s plenum air
temperature which, the Appellants acknowledge (Br. 13), Schmidt measures,
is a fuel cell temperature. Regardless, as discussed above regarding
claims 1, 7 and 21, Schmidt would have rendered prima facie obvious, to
one of ordinary skill in the art, monitoring the temperatures of the individual
fuel cell cartridges.
The Appellants argue (Br. 16):
The Piovaccari reference mentions the use of a specific voltage output
to determine an operating mode is that [sic] the linear regulator can
operate at less than 100 mV. See Piovaccari, Col. 3, lines 17-20.
However, this does not suggest that it would have been obvious to
place the power switching device in a linear mode of operation when a
fuel cell temperature has reached an operating temperature and when
the difference between the output voltage and the fuel cell voltage is
less than 3.0 volts, as recited in claim 18. The Piovaccari reference
goes on to state that the efficiency of the linear regulator at high
voltage differentials is poor. See Piovaccari, Col. 3, lines 17-21.
Therefore, the Piovaccari reference teaches away from using the linear
regulator at voltages that approach 3.0 volts since its efficiency is
compromised as the voltage differential increases, especially since
voltage levels approaching 3.0 volts is [sic, are] substantially larger
than the typical 100 mV upper threshold mentioned in the Piovaccari
reference.

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Appeal 2008-5923
Application 11/266,987

Piovaccari does not disclose that 100 mV is an upper threshold but,
rather, discloses that a linear regulator “can operate at a smaller input-output
differential voltage, often less than 100 mV, depending on the rated output
current” (col. 3, ll. 18-20). Piovaccari then teaches that if the control circuit
current is much smaller than the load current, the efficiency of a linear
regulator is approximately Vout/Vin (col. 3, ll. 23-27). That disclosure would
have led one of ordinary skill in the art, through no more than ordinary
creativity, to transition a power converter between switched mode (i.e.,
pulse-width modulated mode) and linear regulator mode at a voltage
differential such as 3.0 volts, as in a fuel cell, provided that Vout/Vin is
sufficiently large that the linear regulator is efficient at that voltage
differential. See KSR, 127 S. Ct. at 1741.
Regarding the claim 18 requirement that the transition takes place at
an operating temperature, Piovaccari’s disclosure that the transition is
desirable when, after operating in the switched mode, the output voltage
decreases (col. 3, ll. 48-60), would have indicated to one of ordinary skill in
the art that the transition takes place at an operating temperature, i.e., the
temperature at the end of the switch-mode operation.
Conclusion of Law
The Appellants have not shown reversible error in the Examiner’s
determination that the applied references would have rendered prima facie
obvious, to one of ordinary skill in the art, a fuel cell system comprising a
power switching device that is in a linear mode of operation when the fuel
cell temperature has reached an operating temperature and when the
difference between the output voltage and the fuel cell voltage is less than
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Appeal 2008-5923
Application 11/266,987

3.0 volts, and is in a pulse-width modulated mode of operation when the fuel
cell temperature has reached an operating temperature and the difference
between the output voltage and the fuel cell voltage is at least 3.0 volts.
DECISION/ORDER
The rejection of claims 1-5 and 7-11 under 35 U.S.C. § 102(e) over
Treece is reversed. The rejections under 35 U.S.C. § 103 of claims 1-5, 7-
11, and 18 over Fuglevand in view of Schmidt and Piovaccari, and claim 21
over Fuglevand in view of Schmidt are affirmed.
It is ordered that the Examiner’s decision is affirmed.
No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a).
AFFIRMED

PL Initial:
sld

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