U.S. patent application number 11/997581 was filed with the patent office on 2008-09-25 for fuel cell with fuel monitoring system and method of use.
This patent application is currently assigned to Societe BIC. Invention is credited to Andrew J. Curello, Michael Curello, Floyd Fairbanks, Charles Loonis, Hung T. Than.
Application Number | 20080231836 11/997581 |
Document ID | / |
Family ID | 37727852 |
Filed Date | 2008-09-25 |
United States Patent
Application |
20080231836 |
Kind Code |
A1 |
Curello; Andrew J. ; et
al. |
September 25, 2008 |
Fuel Cell with Fuel Monitoring System and Method of Use
Abstract
A fuel cell (9) includes a removable and replaceable fuel supply
(12) having fuel disposed therein. A system for monitoring various
parameters of the fuel such as temperature, pressure, and the
levels of dissolved oxygen is provided. A plurality of sensors (30)
is disposed on the fuel supply side that is capable of
communicating with a controller (18) and memory (13) on the fuel
cell side. In another embodiment, at least one sensor for measuring
a system parameter of the fuel communicates with an RFID tag (50)
either remotely or via a hardwired link. The sensor and/or the RFID
tag may be coated with a substance impervious to the caustic fuel.
An RFID reader station collects the data. The controller may be
included to use the data in real time to alter system parameters,
such as fuel pumping rates or a bleed off, or to trigger a signal,
such as to notify a user of an empty fuel supply. In another
embodiment, an optical sensor (61, 102) may be used.
Inventors: |
Curello; Andrew J.; (Hamden,
CT) ; Loonis; Charles; (Hamden, CT) ; Than;
Hung T.; (Rockville, MD) ; Curello; Michael;
(Cheshire, CT) ; Fairbanks; Floyd; (Naugatuck,
CT) |
Correspondence
Address: |
THE H.T. THAN LAW GROUP
WATERFRONT CENTER SUITE 560, 1010 WISCONSIN AVENUE NW
WASHINGTON
DC
20007
US
|
Assignee: |
Societe BIC
Clichy Cedex
FR
|
Family ID: |
37727852 |
Appl. No.: |
11/997581 |
Filed: |
July 28, 2006 |
PCT Filed: |
July 28, 2006 |
PCT NO: |
PCT/US06/29685 |
371 Date: |
February 1, 2008 |
Current U.S.
Class: |
356/72 |
Current CPC
Class: |
Y02E 60/50 20130101;
H01M 2250/30 20130101; H01M 8/04425 20130101; H01M 8/04201
20130101; H01M 8/04313 20130101; H01M 8/04089 20130101; H01M
8/04753 20130101; H01M 8/04208 20130101; H01M 8/0432 20130101; H01M
8/04373 20130101; Y02B 90/10 20130101; H01M 8/04388 20130101; G01N
2035/00782 20130101; H01M 8/04186 20130101 |
Class at
Publication: |
356/72 |
International
Class: |
G01N 21/00 20060101
G01N021/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 2, 2005 |
US |
11196685 |
Claims
1-42. (canceled)
43. An optical sensor to monitor a fuel supply for a fuel cell,
said fuel cell comprises a reader capable of reading an optical
signal from said optical sensor to monitor the fuel supply.
44. The optical sensor of claim 43, wherein the fuel cell further
comprises a light source and said light source transports light to
the optical sensor.
45. The optical sensor of claim 44, wherein the optical sensor is
connected to an optical fiber.
46. The optical sensor of claim 43, wherein the optical sensor
comprises a color identification tag.
47. The optical sensor of claim 46, wherein the color
identification tag comprises a plurality of colors.
48. The optical sensor of claim 46, wherein the color
identification tag comprises a color pattern.
49. The optical sensor of claim 46, wherein the color
identification comprises a material exhibiting chromism.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of commonly
owned, co-pending U.S. application Ser. No. 11/196,685, filed on
Aug. 2, 2005, the disclosures of which is incorporated herein by
reference.
FIELD OF THE INVENTION
[0002] The invention relates generally to fuel cells and monitoring
technologies. In particular, sensor arrays linked to a remote
control system and information storage device are used to monitor
system parameters in a fuel cell.
BACKGROUND OF THE INVENTION
[0003] Fuel cells are devices that directly convert chemical energy
of reactants, i.e., fuel and oxidant, into direct current (DC)
electricity. For an increasing number of applications, fuel cells
are more efficient than conventional power generation, such as
combustion of fossil fuel, as well as portable power storage, such
as lithium-ion batteries.
[0004] In general, fuel cell technology includes a variety of
different fuel cells, such as alkali fuel cells, polymer
electrolyte fuel cells, phosphoric acid fuel cells, molten
carbonate fuel cells, solid oxide fuel cells and enzyme fuel cells.
Today's more important fuel cells can be divided into several
general categories, namely: (i) fuel cells utilizing compressed
hydrogen (H.sub.2) as fuel; (ii) proton exchange membrane (PEM)
fuel cells that use alcohols, e.g., methanol (CH.sub.3OH), metal
hydrides, e.g., sodium borohydride (NaBH.sub.4), hydrocarbons, or
other fuels reformed into hydrogen fuel; (iii) PEM fuel cells that
can consume non-hydrogen fuel directly or direct oxidation fuel
cells; and (iv) solid oxide fuel cells (SOFC) that directly convert
hydrocarbon fuels to electricity at high temperature.
[0005] Compressed hydrogen is generally kept under high pressure
and is therefore difficult to handle. Furthermore, large storage
tanks are typically required and cannot be made sufficiently small
for consumer electronic devices. Conventional reformat fuel cells
require reformers and other vaporization and auxiliary systems to
convert fuels to hydrogen to react with oxidant in the fuel cell.
Recent advances make reformer or reformat fuel cells promising for
consumer electronic devices. The most common direct oxidation fuel
cells are direct methanol fuel cells or DMFC. Other direct
oxidation fuel cells include direct ethanol fuel cells and direct
tetramethyl orthocarbonate fuel cells. DMFC, in which methanol is
reacted directly with oxidant in the fuel cell, has promising power
application for consumer electronic devices. SOFC convert
hydrocarbon fuels, such as butane, at high heat to produce
electricity. SOFC requires relatively high temperature in the range
of 1000.degree. C. for the fuel cell reaction to occur.
[0006] The chemical reactions that produce electricity are
different for each type of fuel cell. For DMFC, the
chemical-electrical reaction at each electrode and the overall
reaction for a direct methanol fuel cell are described as
follows:
[0007] Half-reaction at the anode:
CH.sub.3OH+H.sub.2O.fwdarw.CO.sub.2+6H.sup.++6e.sup.-
[0008] Half-reaction at the cathode:
1.5O.sub.2+6H.sup.++6e.sup.-.fwdarw.3H.sub.2O
[0009] The overall fuel cell reaction:
CH.sub.3OH+1.5O.sub.2.fwdarw.CO.sub.2+2H.sub.2O
[0010] Due to both the migration of the hydrogen ions (H.sup.+)
through the PEM from the anode to the cathode and the inability of
the free electrons (e.sup.-) to pass through the PEM, the electrons
flow through an external circuit, thereby producing an electrical
current. The external circuit may be used to power many useful
consumer electronic devices, such as mobile or cell phones,
calculators, personal digital assistants, laptop computers, and
power tools, among others.
[0011] DMFC is discussed in U.S. Pat. Nos. 5,992,008 and 5,945,231,
which are incorporated herein by reference in their entireties.
Generally, the PEM is made from a polymer, such as Nafion.RTM.
available from DuPont, which is a perfluorinated sulfonic acid
polymer having a thickness in the range of about 0.05 mm to about
0.5 mm, or other suitable membranes. The anode is typically made
from a Teflonized carbon paper support with a thin layer of
catalyst, such as platinum-ruthenium, deposited thereon. The
cathode is typically a gas diffusion electrode in which platinum
particles are bonded to one side of the membrane.
[0012] In another direct oxidation fuel cell, borohydride fuel cell
(DBFC) reacts as follows:
[0013] Half-reaction at the anode:
BH.sub.4-+8OH--.fwdarw.BO.sub.2.sup.-+6H.sub.2O+8e-
[0014] Half-reaction at the cathode:
2O.sub.2+4H.sub.2O+8e-.fwdarw.8OH--
[0015] In a chemical metal hydride fuel cell, generally aqueous
sodium borohydride is reformed and reacts as follows:
NaBH.sub.4+2H.sub.2O.fwdarw.(heat or
catalyst).fwdarw.4(H.sub.2)+(NaBO.sub.2)
[0016] Half-reaction at the anode:
H.sub.2.fwdarw.2H++2e.sup.-
[0017] Half-reaction at the cathode:
2(2H.sup.++2e.sup.-)+O.sub.2.fwdarw.2H.sub.2O
[0018] Suitable catalysts for this reaction include platinum and
ruthenium, as well as other metals. The hydrogen fuel produced from
reforming sodium borohydride is reacted in the fuel cell with an
oxidant, such as O.sub.2, to create electricity (or a flow of
electrons) and water byproduct. A sodium borate (NaBO.sub.2)
byproduct is also produced by this process. A sodium borohydride
fuel cell is discussed in U.S. Pat. No. 4,261,956, which is
incorporated herein by reference. Therefore, the known chemical
hydride reactions that use aqueous metal hydride have about 9 to 12
weight percentage storage expectancy, and the liquid and the
catalyst used in the wet chemical reaction system need to be
closely monitored. Additionally, it is difficult to maintain the
stability of a metal hydride solution over a long period of time,
because according to the formula t1/2-pH*log(0.034+kT), which
provides the half life of the reaction, the reaction of hydrolysis
always occurs very slowly. Furthermore, if the solution is
stabilized, the reactivity is not complete.
[0019] In a hydride storage method, the reaction is as follows:
Metal+H.sub.2.fwdarw.hydride+heat
[0020] However, storage expectancy of such a reaction is only about
5 weight percentage. Additionally, such reactions can be expensive
and difficult to package.
[0021] Another known method to produce hydrogen is a dry hydride
reaction. Dry reaction, generally, involves the following
reaction:
X(BH.sub.4).fwdarw.H.sub.2, where X includes, but is not limited
to, Na, Mg, Li, etc.
[0022] Again, dry reactions have several disadvantages, such as
having a storage expectancy of only about 10 weight percentage, and
the need to closely monitor the pressure.
[0023] An additional method to produce hydrogen gas is by a
pressure storage method using the formula PV=nRT, wherein P is
pressure, V is volume, n is a number of moles, R is the gas
constant, and T is temperature. This method requires constant
pressure monitoring.
[0024] One of the most important features for fuel cell application
is fuel storage. Another important feature is regulating the
transport of fuel out of the fuel cartridge to the fuel cell. To be
commercially useful, fuel cells such as DMFC or PEM systems should
have the capability of storing sufficient fuel to satisfy the
consumers' normal usage. For example, for mobile or cell phones,
for notebook computers, and for personal digital assistants (PDAs),
fuel cells need to power these devices for at least as long as the
current batteries and, preferably, much longer. Additionally, the
fuel cells should have easily replaceable or refillable fuel tanks
to minimize or obviate the need for lengthy recharges required by
today's rechargeable batteries.
[0025] In the operation of a fuel cell, monitoring various system
parameters in real time is highly desirable for a number of
reasons. First, tracking the fuel usage history indicates the
amount of fuel remaining in the fuel supply and provides the user
with information regarding the remaining useful life of the fuel
supply. The patent literature discloses a number of containers for
consumable substances that include electronic memory components.
United States patent application publication no. US 2002/0154815,
which is incorporated herein in its entirety by reference,
discloses a variety of containers that may include read-only
memories, programmable read-only memories, electronically erasable
programmable read-only memories, non-volatile random access
memories, volatile random access memories or other types of
electronic memory. These electronic memory devices may be used to
retain coded recycle, refurbishing and/or refilling instructions
for the containers, as well as a record of the use of the
containers. The containers may comprise liquid ink or powdered
toner for a printer. Alternatively, the containers or fuel supply
may comprise a fuel cell or a fuel supply therefor.
[0026] Also, the transfer of the fuel from the fuel supply to the
fuel cell may depend upon, inter alia, the viscosity of the fuel.
For example, the viscosity of methanol, which is about
8.17.times.10.sup.-4 Pa-s at 1 atmosphere and 0.degree. C., drops
to about 4.5.times.10.sup.-4 Pa-s at 1 atmosphere and 40.degree.
C., representing about a 50% reduction. If the system is able to
detect in real time the temperature and/or pressure of the fuel
contained within the fuel supply, then the fuel cell can
self-regulate how long a fuel pump should run in order to provide
an appropriate amount of fuel. As fuel is supplied at the optimum
rate, the efficiency of the system is increased. Also, monitoring
the pressure of the fuel within the fuel supply can alert the user
or the system of unacceptable high or unacceptable low pressure
levels. Furthermore, the usable life of the fuel cell can be
increased if exposure to fuel is limited to the amount of fuel
necessary for operation. In other words, flooding the fuel cell
with excess fuel may damage the fuel cell.
[0027] One option among others for a monitoring system is using a
radio frequency identification (RFID) system. Systems using RFID
technologies are well known, particularly for uses such as tracking
inventory such as library or retail store inventory, automated
payment systems such as passes for toll booths, and security
systems such as smart keys for starting a car. Such systems may be
large and active systems, utilizing battery-powered transceiver
circuitry. Such systems may also be very small and passive, in
which a transponder receives power from the base station or reader
only when information is desired to be transmitted or
exchanged.
[0028] A typical RFID system includes a reusable identifying device
typically referred to as a tag, but sometimes designated as a
"card," "key," or the like. The RFID system also requires a
recognition or reader station that is prepared to recognize
identifying devices of predetermined characteristics when such
identifying device is brought within the proximity of the reader
station. Typically, a reader station includes an antenna system
that reads or interrogates the tags via a radio frequency (RF) link
and a controller. The controller directs the interrogation of the
tags and may provide memory for storing the data collected from the
tags. Further, the controller may provide a user interface so that
a user may externally monitor the data.
[0029] In operation, as a tag comes within sufficient proximity to
an RFID reader station, the antenna emits RF signals towards the
tag and the tag transmits responses to the antenna. The tags can be
powered by an internal battery (an "active" tag) or by inductive
coupling receiving induced power from the RF signals emitted from
the antenna (a "passive" tag). Inductive coupling takes place
between the two devices when they are proximate to one another;
physical contact is unnecessary. Passive tags have zero maintenance
and virtually unlimited life. The life span of an active tag is,
however, limited by the lifetime of the battery, although some tags
offer replaceable batteries.
[0030] Current monitoring systems with RFID tags have not been
adapted for use with fuel cell systems, either in terms of the type
of data desired to be monitored or in terms of the ability of the
system to withstand the harsh environment due to contact with fuel
cell fuels. It would, therefore, be desirable to provide an RFID
monitoring system and other types of monitoring systems for use
with a fuel cell system.
SUMMARY OF THE INVENTION
[0031] Briefly, in accordance with one aspect of the present
invention, a system for monitoring a fuel cell includes a fuel cell
supply connected to a fuel cell. A plurality of sensors is
operatively connected to the fuel supply. A controller is connected
to the fuel cell and to an optional information storage device. A
sensor communication link connects the plurality of sensors and the
controller. A memory communication link connects the controller and
the optional information storage device
[0032] According to another aspect of the present invention, a fuel
supply for a fuel cell includes a container having fuel disposed
therewithin. A sensor for monitoring a condition of the fuel is
located on or within the fuel supply. An RFID tag is configured to
communicate with the sensor and adapted to be interrogated by an
RFID reader station.
[0033] According to another aspect of the present invention, a fuel
supply for a fuel cell includes at least one optical sensor, such
as a color identification tag or a sensor located on an optical
fiber, disposed on or within the supply. A device powered by the
fuel cell, a functional unit connected to the fuel cell or the fuel
cell may contain a color reader capable of reading the optical
sensor to confirm that a proper fuel supply has been inserted or to
monitor the condition(s) of the fuel supply, e.g. temperature and
pressure.
[0034] According to another aspect of the present invention, a
method for monitoring a condition of fuel within a fuel cell
comprises the steps of (1) providing a fuel cell connected to a
fuel supply containing a fuel; (2) collecting data regarding the
fuel using a plurality of sensors; (3) relaying the information
from the sensor to a controller and optionally to an information
storage device, wherein the plurality of sensors is located in or
on the fuel supply and the information storage device is located
remotely from the plurality of sensors.
BRIEF DESCRIPTION OF THE DRAWINGS
[0035] These and other features, aspects, and advantages of the
present invention will become better understood when the following
detailed description is read with reference to the accompanying
drawings in which like characters represent like parts throughout
the drawings, wherein:
[0036] FIG. 1 is a perspective break-away view of a fuel cell
system according to the present invention;
[0037] FIG. 1a is a schematic view of an alternate embodiment of a
fuel cell system according to the present invention incorporating
passive optical sensors;
[0038] FIG. 2 is a schematic view of a fuel cell system according
to the present invention, wherein a sensor array is connected to a
remotely located controller and information storage device;
[0039] FIG. 3 is a schematic view of a fuel cell system according
to the present invention, wherein a monitoring system in a fuel
cartridge is remotely linked to a controller and information
storage device;
[0040] FIG. 4 is a schematic view of a second embodiment of the
fuel cell system of the present invention, wherein sensors of the
monitoring system are remotely linked to an RFID tag;
[0041] FIG. 5 is a schematic view of a fuel cell system according
to a third embodiment of the present invention, wherein the RFID
tag is fixedly attached to an interior surface of the fuel
cartridge;
[0042] FIG. 6 is a schematic view of a fuel supply according to the
present invention having an RFID tag affixed to an outer surface
thereof;
[0043] FIG. 7 is a schematic view of a fuel supply according to the
present invention having an RFID tag affixed to an outer surface
thereof with an insulating materials; and
[0044] FIG. 8 is another embodiment similar to FIG. 1 illustrating
an alternate color I.D. tag.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0045] As illustrated in the accompanying drawings and discussed in
detail below, the present invention is directed to a fuel supply,
which stores fuel cell fuels such as methanol and water,
methanol/water mixture, methanol/water mixtures of varying
concentrations or pure methanol. Methanol is usable in many types
of fuel cells, e.g., DMFC, enzyme fuel cell and reformat fuel cell,
among others. The fuel supply may contain other types of fuel cell
fuels, such as ethanol or other alcohols, chemicals that can be
reformatted into hydrogen, or other chemicals that may improve the
performance or efficiency of fuel cells. Fuels also include
potassium hydroxide (KOH) electrolyte, which is usable with metal
fuel cells or alkali fuel cells, and can be stored in fuel
supplies. For metal fuel cells, fuel is in the form of fluid-borne
zinc particles immersed in a KOH electrolytic reaction solution,
and the anodes within the cell cavities are particulate anodes
formed of the zinc particles. KOH electrolytic solution is
disclosed in United States published patent application no.
2003/0077493, entitled "Method of Using Fuel Cell System Configured
to Provide Power to One or more Loads," published on Apr. 24, 2003,
which is incorporated herein by reference in its entirety. Fuels
also include a mixture of methanol, hydrogen peroxide and sulfuric
acid, which flows past a catalyst formed on silicon chips to create
a fuel cell reaction. Fuels also include a blend or mixture or
methanol, sodium borohydride, an electrolyte and other compounds,
such as those described in U.S. Pat. Nos. 6,554,877, 6,562,497 and
6,758,871, which are incorporated by reference in their entireties.
Fuels also include those that are partially dissolved in solvent
and partially suspended in solvent, described in U.S. Pat No.
6,773,470 and those that include both liquid fuel and solid fuels,
described in United States published patent application number
2002/076602. Both of these references are also incorporated by
reference in their entireties.
[0046] Fuels also include metal hydrides, such as sodium
borohydride (NaBH.sub.4) and water, discussed above. Fuels further
include hydrocarbon fuels, which include, but are not limited to,
butane, kerosene, alcohol and natural gas, disclosed in United
States published patent application no. 2003/0096150, entitled
"Liquid Hereto-Interface Fuel Cell Device," published on May 22,
2003, which is incorporated herein by reference in its entirety.
Fuels also include liquid oxidants that react with fuels. The
present invention is, therefore, not limited to any type of fuels,
electrolytic solutions, oxidant solutions or liquids or solids
contained in the supply or otherwise used by the fuel cell system.
The term "fuel" as used herein includes all fuels that can be
reacted in fuel cells or in the fuel supply, and includes, but is
not limited to, all of the above suitable fuels, electrolytic
solutions, oxidant solutions, gasses, liquids, solids and/or
chemicals and mixtures thereof.
[0047] As used herein, the term "fuel supply" includes, but is not
limited to, disposable cartridges, refillable/reusable cartridges,
containers, cartridges that reside inside the electronic device,
removable cartridges, cartridges that are outside of the electronic
device, fuel tanks, fuel reservoirs, fuel refilling tanks, other
containers that store fuel and the tubings connected to the fuel
tanks and containers. While a cartridge is described below in
conjunction with the exemplary embodiments of the present
invention, it is noted that these embodiments are also applicable
to other fuel supplies and the present invention is not limited to
any particular type of fuel supplies.
[0048] The fuel supply of the present invention can also be used to
store fuels that are not used in fuel cells. These applications
include, but are not limited to, storing hydrocarbons and hydrogen
fuels for micro gas-turbine engines built on silicon chips,
discussed in "Here Come the Microengines," published in The
Industrial Physicist (December 2001/January 2002) at pp. 20-25.
Other applications include storing traditional fuels for internal
combustion engines; hydrocarbons, such as butane for pocket and
utility lighters and liquid propane; as well as chemical fuels for
use in personal portable heating devices. As used herein, the term
"fuel cell" includes fuel cells as well as other machineries usable
with the cartridges of the present invention.
[0049] As illustrated in the figures, the present invention is
directed to a fuel cell system 10 for powering a load 11 (shown in
FIGS. 2-5). Load 11 is typically an electronic device that fuel
cell system 10 powers. Load or electrical device 11 is preferably
the external circuitry and associated functions of any useful
consumer electronic device, although load 11 may also have fuel
cell system 10 integrated therewith. Examples of electronic device
11 include, but are not limited to, mobile or cell phones,
calculators, power tools, gardening tools, personal digital
assistants, digital cameras, laptop computers, computer games
systems, portable music systems (MP3 or CD players), global
positioning systems, and camping equipment, among others.
[0050] Referring to FIG. 1, the first embodiment of fuel cell
system 10 includes a fuel cell 9 having a fuel cell housing 17 and
a fuel supply 12 having a fuel supply housing 21. Also contained
within fuel cell housing 17 is preferably a pump 14 for
transferring fuel from fuel supply 12 to fuel cell units 16.
Suitable pumps 14, including but not limited to piezo-electric
pumps, are fully disclosed in the patent publication no. U.S.
2005/0118468, and also in commonly owned, co-pending United States
patent publication nos. U.S. 2004/0151962; entitled "Fuel Cartridge
for Fuel Cells," filed on Jan. 31, 2003, U.S. 2005/0023236;
entitled "Fuel Cartridge with Flexible Liner," filed on Jul. 29,
2003; and U.S. 2005/0022883, entitled "Fuel Cartridge with
Connecting Valve," filed on Jul. 29, 2003. The disclosures of these
references are incorporated herein by reference in their
entireties. In another embodiment, fuel supply 12 is a pressurized
fuel supply, which automatically controls the amount of fuel
transferred to fuel cell 9 based upon the internal pressure of fuel
supply 12 as discussed in the U.S. 2005/0023236 publication, among
other references. As is described in commonly owned, co-pending
U.S. patent application publication nos. 2005/0074643, entitled
"Fuel Cartridges for Fuel Cells and Methods for Making Same," filed
on Oct. 6, 2003; Ser. No. 11/067,167, entitled "Hydrogen Generating
Fuel Cell Cartridges," filed on Feb. 25, 2005; and Ser. No.
11/066,573, entitled "Hydrogen Generating Fuel Cell Cartridges,"
filed on Feb. 25, 2005, as well as commonly-owned, co-pending U.S.
provisional application Ser. No. 60/689,538, entitled
"Hydrogen-Generating Fuel Cell Cartridges," and 60/689,539,
entitled "Hydrogen-Generating Fuel Cell Cartridges," both of which
were filed on Jun. 13, 2005, the internal pressure of fuel supply
dictates whether or not additional fuel is produced within the fuel
supply. The disclosures of all of the above-listed references are
incorporated herein by reference in their entireties. In this case,
the internal pressure of the pressure cartridge is preferably
monitored with a pressure sensor.
[0051] Fuel cell 9 includes several fuel cell units 16 arranged
into stacks. Fuel cell units 16 may be any type of fuel cell unit
known in the art, as discussed above. Fuel cell units 16 may
include at least a PEM sandwiched between an anode layer and a
cathode layer. Typically, several sealing layers are also included
with fuel cell unit 16. As described above, fuel cell units 16
generate free electrons, i.e., electricity, to power electronic
device 11.
[0052] With further reference to FIG. 1, fuel supply 12 comprises
an outer shell or casing 21 and a nozzle 22. Nozzle 22 houses
shut-off valve 24 (shown in FIGS. 2-5), which is in fluid
communication with the fuel stored in fuel supply 12. Shut-off
valve 24 in turn is connected to pump 14. Suitable shut-off valves
24 are fully disclosed in publication U.S. 2005/0022883. Pump 14 is
optional if fuel supply 12 is pressurized; in such a case, pump 14
may be replaced by a valve.
[0053] The size and shape of fuel cell housing 17 need only be
sufficient to contain fuel cell units 16, pump 14, controller 18,
and information storage device 13. Fuel cell housing 17 is also
preferably configured to receive fuel cartridge housing 21. Housing
17 is preferably configured such that fuel supply 12 is easily
connectable to housing 17 by the consumer/end user. Supply 12 can
be formed with or without an inner liner or bladder. Cartridges
without liners and related components are disclosed in publication
U.S. 2004/0151962. Cartridges with inner liners or bladders are
disclosed in publication U.S. 2005/0023236.
[0054] Controller 18 is preferably provided within housing 17 to
control the functions of electronic device 11, supply 12, pump 14
and fuel cell units 16, among other components. Alternatively,
controller 18 may be remotely located from fuel cell system 10 and
connected thereto via a communications transmission link, such as a
radio frequency link or an optical link. Preferably, housing 17
also supports at least one optional battery 19 for powering various
components of system 10 and electronic device 11 when fuel cell 9
is not operating or during system start-up, shut down, or when
otherwise necessary. Alternatively, optional battery 19 powers
controller 18 when fuel supply 12 is empty or when the fuel cell 9
is off. Optional battery 19 can be replaced by or used in
conjunction with solar panels. Additionally, optional battery 19
may be recharged by fuel cell 9 or another appropriate source, such
as a wall outlet or solar panels.
[0055] In the present invention, a monitoring system is included
with fuel cell system 10. Monitoring system includes a plurality of
sensors 30 for monitoring one or more parameters of the fuel
contained within fuel cell supply 12. In the first embodiment as
shown in FIG. 1, plurality of sensors 30 are located on a single
sensor chip 28, which is preferably an integrated circuit chip.
Preferably, neither plurality of sensors 30 nor sensor chip 28
contain memory; the information gathered by sensors 30 are relayed
to controller 18 and could be stored in information storage device
13, which is described in greater detail hereinafter. In an
alternate embodiment, however, sensor chip 28 may contain memory
similar to information storage device 13.
[0056] Typically, several fuel parameters should be monitored. For
example, the parameters include but are not limited to pressure,
temperature, the presence and levels of dissolved gasses, ion
concentrations, fuel density, the presence of impurities, duration
of use, stress and strain to which fuel supply is subjected, as
well as the amount of fuel remaining within the fuel cartridge.
Preferably, at least one of sensors 30 is a pressure sensor. The
pressure sensor may be any type of pressure sensor known in the art
that is capable of being placed in fuel supply 12 and measuring
pressure in the anticipated range of approximately 0-40 psi,
although this range may vary depending upon the fuel cell system
and fuel used. For example, the pressure sensor may be a pressure
transducer available from Honeywell, Inc. of Morristown, N.J. The
pressure sensor may also be a glass or silica crystal that behaves
like a strain gauge, i.e., the crystal emits a current depending
upon the amount of pressure. The pressure sensor may be used alone
or in conjunction with other sensors monitoring different aspects
of the fuel.
[0057] The pressure can also be sensed by a piezoelectric sensor.
Piezoelectric sensors are solid state elements that produce an
electrical charge when exposed to pressure or to impacts. Changes
in pressure inside the fuel supply due to internal pressure or
impacts cause a signal to be produced from the sensor, which can be
transmitted to the controller for processing or action. Suitable
piezoelectric sensors are available from many sources, including
PCB Piezotronics. Additionally, the piezoelectric sensor can also
be configured to measure a force acting on the fuel supply or on
the fuel cell system, and can also act as an accelerometer so that
if the fuel supply is dropped the sensor would recognize the
acceleration and signals the controller for actions, e.g., shut
down or fail-safe operations. The piezoelectric sensors can be
located on fuel supply 12, on fuel cell system 10 or on electronic
device 11.
[0058] The pressure can also be sensed by an optical sensor. The
use of passive optical sensors is well known, as discussed, for
example, in U.S. Pat. No. 4,368,981, the disclosure of which is
incorporated herein in its entirety by reference. As shown in FIG.
1A, fuel cell 9 includes a light source 60, such as a variable
wavelength laser, a light emitting diode, or similar source of
visible or non-visible radiation. Fuel cell 9 also includes at
least one photodetector 64. Both light source 60 and photodetector
64 are linked to controller 18. An optically invisible window 62a
is disposed on a surface of housing 17 facing fuel supply 12 so
that the aperture of light source 60 is aligned with window 62a.
Similarly, a second optically invisible window 62b is disposed on a
surface of casing 21 so that when fuel supply 12 is attached to
fuel cell 9, window 62a aligns with window 62b. Optically connected
to window 62b within fuel supply 12 is at least one sensor 30. One
of sensors 30 can be optical sensor 61 which may be any passive
optical sensor known in the art, such as an interferometer, a
Michelson sensor, a Fabry-Perot sensor and the like. In one
embodiment, optical sensor 61 generally includes two coils of
optical fiber which initially have the same length. An exposed
optical fiber 63a is subjected to environmental conditions within
fuel supply 12, while a reference coil of optical fiber 63b is
shielded therefrom. In one example, exposed coil 63a is wrapped
around a fuel liner and reference coil 63b is positioned inside the
fuel liner, on an exterior surface of the outer casing, or between
the fuel liner and the outer casing. If the pressure in the fuel
liner increases then the liner would increase in volume, thereby
stretching the exposed fiber. The difference between the exposed
and the reference coils indicates an increase in pressure.
Additionally since both fiber coils are at substantially the same
temperature, this optical sensor is not sensitive to temperature.
In the event that the exposed fiber is broken due to the pressure
in the liner, the failure of the light in exposed coil 63a to reach
photodetector 64 or optional photodetector 64a may also indicate
high pressure.
[0059] In operation, light source 60 emits light, preferably a
pulse of known duration, which shines through window 62a and into
window 62b. The light is optically transferred to both coils 63a,
63b at the same time. The light travels through coils 63a, 63b and
is reflected back through windows 62b and 62a. The light signals
are detected by photodetector 64. Optionally, photo detector 64
comprises detectors 64a, 64b corresponding to coils 63a and 63b. As
pressure increases within fuel supply 12, the length of exposed
coil 63a increases relative to the length of reference fiber 63b,
causing a slight delay in receiving the signal from coil 63a. From
this time delay, the pressure within fuel supply 12 may be
calculated by controller 18.
[0060] One of sensors 30 may also be a temperature sensor. The
temperature sensor can be any type of temperature sensor known in
the art, such as a thermocouple, a thermistor, or an optical
sensor. Anticipated typical temperatures desired to be monitored
range from about -20 to 55 degrees centigrade. A temperature sensor
may be used alone or in conjunction with other sensors monitoring
different aspects of the fuel. If an optical sensor is used, the
type and method of operation thereof is substantially similar to
that described above with respect to the pressure within fuel
supply 12.
[0061] One of sensors 30 may also be a sensor for measuring
dissolved gases, such as an oxygen or hydrogen sensor. These
dissolved gas sensors may be any type known in the art. For
example, one type of appropriate oxygen sensor is a galvanic cell,
including an anode and a cathode surrounded by an electrolytic
solution. The galvanic cell produces an electric current
proportional to the pressure of detected oxygen. The dissolved gas
sensor may be used alone or in conjunction with other sensors
monitoring different aspects of the fuel.
[0062] One of sensors 30 may be a fuel gauge. One type of fuel
gauge suitable for use on a chip 28 is a thermistor (also
thermister) which can be used to measure the remaining fuel in fuel
supply 12. A thermistor is a semi-conducting resistor that is
sensitive to temperature changes. In other words, the resistance of
the thermistor changes as the temperature changes. Generally, there
are two types of thermistors: negative temperature coefficient
(NTC) thermistors and positive temperature coefficient (PTC)
thermistors. NTC thermistors display a decrease in its resistance
when exposed to increasing temperature, and PTC thermistors display
an increase in its resistance when exposed to increasing
temperature. Thermistors have been traditionally used to measure
the temperature of a system or a fluid. The use of thermistors as a
fuel gauge is discussed in detail in patent application publication
no. U.S. 2005/0115312, which is incorporated by reference in its
entirety.
[0063] An important aspect of the thermistor's resistance depends
on the thermistor's body temperature as a function of the heat
transfer inside the fuel cartridge and the heat transfer within the
electronic device that the fuel cell powers. Heat transfer occurs
mainly by conduction and radiation in this environment or from
heating caused by power dissipation within the device. In
traditional temperature measuring function, self heating must be
compensated so that the accurate temperature can be obtained. In
accordance with the present invention, self heating is not
compensated so that the capacity to dissipate heat of the remaining
fuel inside fuel cartridge can be gauged. The heat capacity is
related to the amount of fuel remaining in the cartridge. Both NTC
and PTC thermistors are usable with the present invention.
[0064] Generally, heat capacitance or heat conductivity is
described as the ability of a fluid, i.e., liquid or gas, to
conduct or dissipate heat. Liquid, such as water or methanol, has a
much higher capacity to dissipate heat than gas, such as air,
carbon dioxide or methanol gas. The capacity of a fluid to
dissipate heat is equal to its heat capacitance, which is a
constant for a particular fluid, multiplied by the fluid volume.
Hence, this aspect of the present invention measures the volume of
the remaining fuel by measuring the electrical resistance of the
thermistor positioned within the fuel or on the optional liner
containing the fuel. The electrical resistance is then converted to
the capacity of the remaining fuel to dissipate heat, and this
capacity is converted to the volume of remaining fuel by dividing
out the heat capacitance constant. In other words, higher heat
capacity corresponds to higher remaining fuel volume.
[0065] The thermistor-fuel gauge should be calibrated prior to use.
The operating temperatures of the fuel cell and of the electronic
device are known. An electrical signal from a full liner is
recorded and then an electrical signal from an empty liner is
recorded. One or more signals from known partial volumes can also
be recorded. A calibration curve can be drawn from these
calibration points between these operating temperatures. A
real-time signal is compared to this calibration curve to determine
the remaining fuel. Other methods of calibrations can be performed
without deviating from the present invention.
[0066] Additionally, since the thermistor is a resistor, electrical
current that flows through the thermistor generates heat.
Therefore, electrical current can flow through the thermistor to
generate heat that can be dissipated by the remaining fuel, and
accurate readings can be obtained. In one embodiment, controller 18
sends the current as a query to the thermistor to gauge the amount
of heat dissipation whenever a remaining fuel reading is desired.
The electrical current can be sent intermittently or
continuously.
[0067] In accordance with another aspect of the present invention,
a thermocouple can be used as a fuel gauge. The use of a
thermocouple as a fuel gauge is described in detail in publication
U.S. 2005/0115312, previously incorporated by reference. A
thermocouple is also typically used to measure temperature and
comprises two wires made from different metals, and is also known
as a bi-metal sensor. The wires are joined at two junctions. A
potential difference is established when a measuring junction is at
a temperature that is different than a temperature at a reference
junction. The reference junction is typically kept a known
temperature, such as the freezing point of water. This potential
difference is a DC voltage which is related to the temperature at
the measuring junction. Using a thermocouple to measure temperature
is well known in the art.
[0068] Similar to the thermistor, a thermocouple acts like a
resistor that is sensitive to temperature. The thermocouple is
capable of measuring the heat capacity of the remaining fuel by
measuring the potential difference. Hence, the thermocouple can
also measure the remaining fuel. Alternatively, electrical current
can be sent through the measuring junction of the thermocouple. The
current heats up the measuring junction and the fuel dissipates the
heat. The amount of heat dissipated, therefore, relates to the
remaining fuel. The current can be sent intermittently or
continuously. The thermocouple fuel gauge should be calibrated
similar to the calibration of the thermistor, discussed above.
[0069] In accordance with another aspect of the present invention,
an inductive sensor can be used to measure the remaining fuel. The
use of inductive sensors as a fuel gauge is described in detail in
publication no. U.S. 2005/0115312, previously incorporated by
reference. Inductive sensors are typically used as on/off proximity
switches. An inductive sensor contains a wire coil and a ferrite
core, which form the inductive portion of an inductive/capacitance
(LC) tuned circuit. This circuit drives an oscillator, which in
turn generates a symmetrical, oscillating magnetic field. When an
electrical conductor, such as a metal plate, enters this
oscillating field, eddy currents are formed in the conductor. These
eddy currents draw energy from the magnetic field. The changes in
the energy correlate to the distance between the inductive sensor
and the electrical conductor.
[0070] One of sensors 30 may also be a clock or other form of
timing or counting mechanism. Examples of the timing mechanism may
include an oscillator, such as a crystal or induction oscillator,
integrated onto chip 28. As the counter relies upon memory such as
information storage device 13, which is preferably housed in fuel
cell 9, the counter counts the oscillations only when fuel supply
12 is connected to fuel cell 9. In this way, the counter may track
how long fuel supply 12 has been in use. The count of oscillations
is preferably stored in information storage device 13. The
oscillator can be powered by an optional battery internal to fuel
supply 12 or may be triggered by power transferred from fuel cell
9, such as when pump 14 is turned on. If information storage device
13 also tracks pumping rates, controller 18 may be programmed to
calculate flow rate of fuel through pump 12 and, consequently, the
remaining fuel in fuel supply 12. In other words, the combination
of a counter and tracking of pumping rates may be used as a fuel
gauge.
[0071] Alternatively, the timing mechanism may include an energy
storage device with a known decaying signature housed in fuel
supply 12. For example, fuel supply 12 could include a battery
whose self-discharge rates are known and a battery tester may be
incorporated into fuel cell 9. It is known in the art that a
typical nickel-based battery discharges approximately 10-15% of its
charge in the first 24 hours after the charge is maximized,
followed by additional 10-15% losses monthly thereafter. Similarly,
it is known that lithium ion batteries self-discharge about 5% in
the first 24 hours after charge and 1-2% monthly thereafter.
Additional information regarding the self-discharge of batteries
and monitoring devices therefor can be found in Isidor Buchmann,
The Secrets of Battery Runtime (April 2001) available on
<http://www.batteryuniversity.com/parttwo-31.htm>, the
disclosure of which is incorporated herein by reference. By
programming controller 18 and information storage device 13 with
the self-discharge curves of batteries that are always fully
charged when installed in or on fuel supply 12, controller 18 can
calculate the age or shelf life of fuel supply 12 based on the
measured charge level of the battery at any point in time after
fuel supply 12 is attached to fuel cell 9.
[0072] Additionally, the monitoring system should be robust. Fuels,
in general, may have degrading effects on materials exposed to the
fuel, and in accordance with one aspect of the present invention
materials for the manufacture of fuel supply 12 and its components
are selected to be compatible with fuels. Chip 28 and/or sensors 30
may be placed in contact with the fuel, such as floated in the fuel
or affixed to an inner surface of casing 21 or the optional liner.
Therefore, the monitoring system should be able to withstand
sustained contact with the fuels used in fuel cells.
[0073] A suitable protective material is silicon dioxide
(SiO.sub.2), which can be applied by vapor deposition or sputtering
technique or other known methods. Silica molecules coalesce on a
substrate as SiO.sub.x where x is 1 or 2. Any protective material
that can be suspended in a solvent can be used.
[0074] Other suitable coatings include, but are not limited to, the
class of epoxy-amine coatings. Such coatings are commercially
available as Bairocade coatings from PPG Industries, Inc. of
Cleveland, Ohio. These types of coatings can be applied using
electro-static guns and cured in infrared ovens to create the gas
barrier. The coatings can also be applied by dipping, spraying or
painting. These coatings are typically used to coat beverage
bottles or cans to protect the beverages inside.
[0075] Additionally, a clear polycrystalline, amorphous linear
xylylene polymer may coat and protect the sensor. Xylylene polymer
is commercially available as Parylene.RTM. from Cookson Specialty
Coating Systems of Indianapolis, Ind. Three suitable Parylene
resins are Parylene N (poly-para-xylylene), Parylene C
(poly-monochloro-para-xylylene) and Parylene D
(poly-dichloro-para-xylylene). Additional discussion of Parylene
can be found in co-owned, co-pending United States patent
publication no. 2006/0030652, entitled "Fuel Supplies for Fuel
Cells," filed on Aug. 6, 2004, the disclosure of which is hereby
incorporated by reference herein in its entirety.
[0076] In accordance with another aspect of the present invention,
a gas barrier film is wrapped around sensors 30 for protection.
Suitable gas barrier films include Mylar.RTM. from DuPont and
various films from the food packaging industry. More detailed
information regarding gas barrier films, including a list of
appropriate films, may be found in publication no. U.S.
2006/0030652, previously incorporated by reference. Other
appropriate materials include polyvinyl alcohol (PVOH), ethylene
vinyl alcohol (EVOH), EVOH bonded to a polyester substrate,
polyvinylidene chloride copolymers (PVDC or Saran), nylon resins,
fluoro-polymers, polyacrylonitrile (PAN), polyethylene naphthalate
(PEN), poly(trimethlylene terephthalate) (PTT), resorcinol
copolymers, liquid crystal polymers, aliphatic polyketones (PK),
polyurethane, polyimide, and blends and copolymers of these
materials.
[0077] Furthermore, sensor 30 may be protected from the fuel by
virtue of being placed within housing 21 but outside of a bladder
or liner, such as liner 27 as shown in FIG. 2 and discussed in
greater detail below. Additional protective coatings and protective
films suitable for the sensors are disclosed in publication no.
U.S. 2006/0030652.
[0078] Referring again to FIG. 1, as chip 28 and information
storage device 13 are preferably located remote from one another,
controller 18 initiates the gathering of information from sensors
30, for example, when fuel supply 12 is first inserted into fuel
cell 9. Controller 18 can transmit a signal and/or power to chip 28
to interrogate the sensors 30. Sensors 30 then take readings which
are preferably passed back to controller 18. The communication
between controller 18 and chip 28 takes place via a link that, in
this embodiment, is hard-wired. Leads 70, preferably electrical
wires, are connected to chip 28 and electrical contacts 15A, which
are disposed on an exterior face of casing 21. Leads 72, also
preferably electrical wires, are connected to controller 18 and
electrical contacts 15B. As will be apparent to those in the art,
leads 70, 72 and contacts 15A, 15B may be any leads or electrical
contacts known in the art. Electrical contacts 15A and 15B are
configured and located such that an electrical connection is
established between controller 18 and chip 28 if fuel supply 12 is
properly inserted into housing 17. To that end, fuel supply 12 and
housing 17 are preferably configured such that fuel supply 12 may
only be inserted into housing 17 in the proper position. For
example, housing 17 may include tabs that protrude into the cavity
for receiving fuel supply 12, and fuel supply 12 may include
coordinating slots into which the tabs may slide. Another example
would be if the perimeter of the cavity on housing 17 for receiving
fuel supply 12 is of an asymmetrical shape and fuel supply 12 has
the same shape. Additional ways to insure proper positioning of
fuel supply within housing 17 are discussed in commonly owned,
co-pending U.S. application Ser. No. 10/773,481, entitled "Datum
Based Interchangeable Fuel Cell Cartridges," filed on Feb. 06,
2004, the disclosure of which is hereby incorporated herein by
reference in its entirety.
[0079] In other embodiments, the communication link between sensors
30 and controller 18 is a wireless system that is capable of
transmitting electrical signals. Suitable wireless transmission
systems include any wireless transmission systems known in the art,
including, inter alia, Blue Tooth technology, radio frequency,
infrared rays, and light transmissions such as from lasers or LEDs
from the fuel cell 9 side to photonic sensors on fuel supply 12.
Such wireless transmissions can also transmit or transfer power to
sensors 30.
[0080] As described in publication no. U.S. 2005/0118468, the fuel
supply may include an information storage device that possesses an
ability to store information such as fuel content including fuel
content during usage, fuel quantity, fuel type, anti-counterfeit
information, expiration dates based on age, manufacturing
information and to receive information such as length of service,
number of refuels, and expiration dates based on usage.
[0081] Information relating the conditions of the fuel may change
over time, and it is useful to monitor and store such information.
However, the conditions of the fuel, e.g., viscosity as a function
of temperature discussed above, can change from the time electronic
device 11 is turned off until it is turned on again, e.g., between
nighttime and daytime. Hence the information stored on a memory
device when the device is turned off may be stale when the device
is turned on again. Hence, in certain circumstances it is desirable
to interrogate sensors 30 instead of reading the information stored
on information storage device 13. Stored information includes
protectable information and rewriteable information.
[0082] Protectable information, which cannot be easily erased,
includes, but is not limited to, type of cartridge; date the
cartridge was manufactured; lot number for the cartridge;
sequential identification number assigned to the cartridge during
manufacturer; date the information storage device was manufactured;
lot number for the information storage device; sequential
identification number assigned to the information storage device;
machine identification number for the cartridge and/or storage
device; shift (i.e., time of day) during which the cartridge and/or
storage device were produced; country where the cartridge and/or
storage device were produced; facility code identifying the factory
where the cartridge and/or storage device were produced; operating
limits, including but not limited to temperature, pressure,
vibration tolerance, etc.; materials used in manufacturing,
anti-counterfeit information; fuel information; such as chemical
formulation; concentration; volume; etc.; intellectual property
information, including patent numbers and registered trademarks;
safety information; security password or identification; expiration
date based on date of manufacturing; shut-down sequence; hot swap
procedure; recycling information; reactant information; fuel gage
type; new software to update fuel cell 9 and/or controller 18; and
fluid sensor information.
[0083] Rewriteable information includes, but is not limited to,
current fuel level and/or current ion level in the fuel; number of
ejections/separations of the cartridge from the electrical device
and/or fuel cell or number of times that the cartridge was
refilled; fuel level on ejection/separation of the cartridge from
the electrical device and/or fuel cell; number of
insertions/connections of the cartridge to the electrical device
and/or fuel cell; fluid level on insertion/connection of the
cartridge to the electrical device and/or fuel cell; current
operation status including rate of power consumption;
acceptance/rejection of a particular electronic device; maintenance
status and marketing information for future cartridge designs;
triggering events; expiration date based on actual usage;
efficiency of the system; operational history of the fuel cell
system; such as temperatures and pressures during selected time
periods (e.g., at start-ups and shut-downs or periodically); and
operational history of the electronic devices, such as number of
digital pictures per cartridge, maximum torque for power tools,
talling minutes and standby minutes for cell phones, number of
address look-ups per cartridge for PDAs, etc.
[0084] Information storage device 13 is preferably an electrical
storage device, such as an EEPROM memory chip as discussed and
disclosed in publication no. U.S. 2005/0118468, previously
incorporated by reference. Suitable information storage devices
include, but are not limited to, random access memory (RAM),
read-only memory (ROM), programmable read-only memory (PROM),
erasable programmable read-only memory (EPROM), electrically
erasable programmable read-only memory (EEPROM), flash memory,
electronically readable elements (such as resistors, capacitance,
inductors, diodes and transistors), optically readable elements
(such as bar codes), magnetically readable elements (such as
magnetic strips), integrated circuits (IC chips) and programmable
logic arrays (PLA), among others. The preferred information storage
device includes PLA and EEPROM, and the present invention is
described herein with the EEPROM. However, it is understood that
the present invention is not limited to any particular type of
information storage device.
[0085] Preferably, information storage device 13 generally has a
substrate (not shown) formed of a "potting material," an integrated
circuit memory chip (not shown), and etched or printed layers or
strips of electrical circuitry or contacts (not shown). The
integrated circuit memory chip (not shown) can be connected to the
substrate (not shown) with a plurality of pins, such as in an
external electronic connector.
[0086] Information storage device 13 is preferably connected to
controller 18 via link 25, preferably an electrical connection.
Alternatively, link 25 is a wireless system that is capable of
transmitting electrical signals between information storage device
13 and controller 18. Suitable wireless transmission systems
include any wireless transmission systems known in the art, such as
Blue Tooth technology, radio frequency, infrared rays, optical
transmissions, etc.
[0087] Information storage device 13 can have any particular memory
size. The memory size is determined by the amount of data needed to
be stored. Suitable memory size typically ranges from about 128
bytes to about 512 K bytes. Memory sizes of 1M bytes and higher are
also commercially available and are usable in the present
invention. Information storage device 13 is also not limited to any
particular dimensions so long that it can fit within housing 17 of
fuel cell 9.
[0088] Information storage device 13 preferably includes portions
13a and 13b. Portion 13a is pre-programmed or set up by the
manufacturer to include read-only (write protected or protectable)
data, discussed above. Controller 18 can read the data in portion
13a of information storage device 13. However, the controller 18
cannot modify or erase the read-only data in portion 13a. Portion
13b is programmed or set up by the manufacturer to include
rewriteable data, discussed above. Controller 18 can read and
write/erase the data in portion 13b. Portions 13a and 13b are
electrically connected to link 25 via conventional electrical wires
or printed circuit boards, etc., known by those of ordinary skill
in the art or by the wireless connections listed above.
[0089] A second embodiment of the present invention is shown in
FIG. 2. In this embodiment, which is similar to the first
embodiment shown and described with respect to FIG. 1, plurality of
sensors 30 is not contained on a chip, but is preferably
distributed throughout fuel supply 12. Fuel supply 12 preferably
includes a liner 27.
[0090] In this embodiment, a fuel gauge may comprise two sensors
placed within or on fuel supply 12. The first sensor should be
placed on a location that moves as the fuel is removed to reflect
the level of fuel remaining in the cartridge. For example, the
first sensor can be placed directly on liner 27. The second sensor
is positioned outside of fuel supply 12, e.g., on fuel cell 9 or
electronic device 11. The second sensor is electrically connected
to either fuel cell 9 or to electronic device 11. An electrical
circuit connected to the second sensor can measure electrical or
magnetic properties between these sensors, which correlate or are
related to the fuel level. The electrical circuit can also be
connected to the first sensor via an electrical wire extending
through the wall of fuel supply 12. This type of fuel gauge is more
completely described in publication no. U.S. 2005/0115312.
[0091] The information collected from sensors 30 may be used in a
variety of ways. For example, if the temperature of the fuel falls,
then the fuel becomes more viscous and, therefore, harder to pump.
Controller 18 may dynamically regulate valve 24 so that sufficient
fuel may be pumped to system 10. Further, by monitoring the heat
cycles to which the fuel is subjected, controller 18 may be
programmed to extrapolate the amount of fuel remaining in fuel
supply 12 and produce a fuel gauge read out.
[0092] As will be recognized by those in the art, the placement of
sensors 30 on or near fuel supply 12 could have many
configurations. For example, sensor chip 28 may be separable from
fuel supply 12. Fuel supply 12 includes at least one port for the
transfer of fuel, such as the port closed by shut-off valve 24. One
of these ports could be adapted so that a pod containing sensor
chip 28 could be removably inserted therein. In a case where
sensors 30 do not need to be in direct contact with the fuel, such
as, for example, if monitoring temperature by contact with a
bladder or liner within fuel supply 12, an access port for a sensor
pod could be placed anywhere on fuel supply 12. Additionally,
sensors 30 could be located within housing 17 of fuel cell 9. In
such a case, the connection of electrical contacts 15B and 15A
(shown in FIG. 1) upon insertion of fuel supply 12 into housing 17
provides sensors 30 access to the fuel within fuel supply 12 for
monitoring.
[0093] In yet another embodiment of the present invention as shown
in FIGS. 3-5, the monitoring system may also include a radio
frequency identification (RFID) tag 50 and an RFID tag reader
station 52. RFID tag 50 may be any RFID tag known in the art. RFID
tag 50 may be passive or active. If RFID tag 50 is active, a power
source, such as a battery, is also required. Generally, RFID tags
include memory, either read-only or read-write, and a radio
frequency transmitter. However, some RFID tags contain no memory,
such as read-only RFID tags that include hardwired identification
circuits. The structure and operation of RFID tags are more fully
described in several U.S. patents, including U.S. Pat. Nos.
4,274,083 and 4,654,658, the disclosures of which are incorporated
herein by reference. Suitable RFID tags are commercially available
from many sources, including Philips Semiconductors of San Jose,
Calif., among others.
[0094] RFID tag 50 preferably includes sufficient read-write memory
to contain the data collected from the sensors (described below),
although RFID tag may also be linked via electrical connection to a
separate information storage device located on fuel cell 9.
[0095] RFID tag 50 may be located anywhere on or within fuel supply
12, for example on the top, bottom, or sides of the exterior
surface of the outer casing 21. In the embodiment shown in FIGS. 2,
3, and 4, RFID tag(s) 50 is disposed within fuel supply 12, i.e.,
RFID tag 50 is floated within the fuel. Alternatively, as shown in
the embodiment shown in FIG. 5, RFID tag 50 is adhered to an
interior surface of fuel supply 12 such as by gluing or
welding.
[0096] RFID tag 50 communicates with RFID reader station 52. RFID
reader station 52 emits a radio frequency signal that communicates
with RFID tag 50 and, in the case of passive RFID tags, powers RFID
tag 50 by induction. As shown in FIGS. 3, 4 and 5, RFID reader
station 52 is preferably located in the body of system 10 separate
from fuel supply 12. Alternatively, as shown in FIG. 5, RFID reader
station 52 may be disposed on or within electronic device 11 to
which system 10 is providing power. RFID reader station 52 may also
be a handheld device or located on an external surface of fuel
supply 12. RFID reader station 52 is also linked, either directly
via a hardwired link or indirectly via a transmitted signal, to
controller 18. Controller 18 thereby triggers an interrogation by
RFID reader station 52 and also receives the information
transmitted to RFID reader station 52 from RFID tag 50.
[0097] In both of these embodiments, RFID tag 50 should be
protected from possible reaction with the fuel. Preferably, RFID
tag 50 may be enclosed or encased in a material that is inert to
the fuel. "Inert", as used in this context, refers to the ability
of the material to withstand lengthy exposure to a fuel such as
methanol. For example, RFID tag 50 may be potted within the same
material used to form outer casing 21. RFID tag 50 may also be
contained within a shell, such as a plastic or metal capsule, as
long as the material chosen for the capsule does not significantly
interfere with the radio frequency signals transmitted or received
by RFID tag 50. Additionally, RFID tag 50 may be coated with any of
the coating materials described above with respect to sensor(s) 30,
such as xylylene.
[0098] In another embodiment, shown in FIG. 6, fuel supply 12
includes an outer casing 21 made of a metal, such as stainless
steel, and fuel contained in a liner 27, similar to the embodiment
described above with respect to FIG. 2. In this embodiment, RFID
tag 50 is preferably elevated away from the surface of outer casing
21 of fuel supply 12 by a mount 78, as outer casing 21 itself may
interfere with the induction process that occurs when RFID reader
station 52 is placed in proximity with RFID tag 50. As such, RFID
tag 50 is preferably spaced away from the surface of outer casing
21, preferably about 5 mm. The actual distance 80, or height of
mount 78, between RFID tag 50 and outer casing 21 depends on many
factors, including, inter alia, the operating range requirements of
the system, i.e., the anticipated distance between RFID tag 50 and
RFID tag reader station 52, the size of RFID tag 50, and the tuning
of RFID tag 50 and RFID tag reader station 52. Mount 78 may be made
of any material, such as plastic, ceramic, or the like. Mount 78 is
preferably affixed to both outer casing 21 and RFID tag 50 using
any method known in the art, such as adhering, such as with an
adhesive or similar bonding agent, or by press-fitting mount 78
into a recess formed within outer casing 21. Alternatively, mount
78 can be an air gap.
[0099] In addition to spacing RFID tag 50 and outer casing 21
apart, other ways of compensating for the interference of a metal
outer casing 21 could be used. For example, as shown in FIG. 7, an
insulating material 82 may be placed between outer casing 21 and
RID tag 50. Preferably, insulating material 82 is a ferrite ceramic
material, as the strong magnetic properties of the ferrite shield
RFID tag 50 from outer casing 21. Additional ways to overcome the
interference of metal outer casing 21 include increasing the
strength of the reader field generated by RFID tag reader station
52 and selecting the relative sizes of the of the RFID tag and RFID
tag reader station coils.
[0100] Sensors 30 may be directly or indirectly linked to RFID tag
50. As shown in FIG. 3, a direct link 40 in this embodiment is an
electrical connection that conveys the data produced by sensor 30
to memory on RFID tag 50. In other words, sensor 30 and RFID tag 50
may be incorporated into one chip prior to insertion into fuel
supply 12. Alternatively, as shown in FIG. 4, sensor 30 may itself
include a radio frequency transmitter 41 that modulates and
transmits a signal to either RFID tag 50 or to controller 18, which
also includes a radio frequency transceiver 43. Sensor 30 may also
be integrated with RFID tag 50 within the same material to form an
RFID package. FIG. 5 shows an embodiment where sensors 30 are
hardwired to RFID tag 50, which is adhered to an interior surface
of casing 21. It will be recognized that RFID tag 50 may also be
located on an exterior surface of casing 21.
[0101] Additionally, RFID tag 50 may be used to upload new software
to fuel cell 9. For example, updated software for controller 18 may
be stored in the memory of RFID tag 50. Upon insertion into housing
17, the new software may be transferred to controller 18 via any of
the described communication links. As will be recognized by those
in the art, other types of information could be stored in the
memory of RFID tag 50, such as product recall alerts, new or
updated calibration data, and the like.
[0102] In accordance with another aspect of the present invention,
sensor 30 may comprise at least one color I.D. tag and more
specifically at least one optical color tag. An exemplary fuel
supply 12 with color I.D. tags 102 is shown in FIG. 8. In one
example, color I.D. tag 102 comprises a single color, which can be
accurately measured by a color reader 104 located on fuel cell 9.
Color reader 104 is connected to processor 18, where the measured
color of color tag 102 is processed to determine, among other
things, whether the correct fuel supply has been inserted. Suitable
color readers include, but are not limited to, spectrophotometers,
which are commercially available as the CM series from Komica
Minolta of Japan, and tristimulus type calorimeters, commercially
available as the CR-10, CR-11, and CR-13 series from Komica
Minolta. These color readers can provide a digital value
representing the color of color tag 102 and are capable of
distinguishing the hues, shade and brightness of a particular
color. When the measured color matches a predetermined value stored
in processor 18, then fuel supply 12 is accepted.
[0103] In another example, color I.D. tag 102 is capable of
changing color responsive to a condition of fuel supply 12, such as
temperature or pressure, among other factors. In this example,
color tag 102 is made from a material that exhibits chromism, i.e.,
a reversible change in the colors of compounds, generally caused by
a change in the electron states of the molecules, induced by
various stimuli. Suitable color changing materials include
thermochromism (induced by heat), photochromism (induced by light,
radiation), electrochromism (induced by electron flow),
solvatochromism (induced by solvent polarity), ionochromism
(induced by ions), halochromism (induced by change in pH),
tribochromism (induced by mechanical friction), and piezochromism
(induced by mechanical pressure).
[0104] A preferred color changing tag 102 is made from a material
exhibiting thermochromism, e.g., liquid crystals where the color
changes as the crystallic structure changes from a low-temperature
crystallic phase through anisotropic chiral/twisted nematic phase
to a high-temperature isotropic liquid phase. Exemplary color
changing liquid crystals include cholesteryl nonanoate or
cyanobiphenyls. Other suitable temperature-induced color changing
materials include leuco dyes.
[0105] In this example, color reader 104 can detect the changes in
the color of color tag 102 in response to a physical condition of
fuel supply 12, e.g., high temperature or high pressure. The change
in color can be processed by processor 18 to monitor the
condition(s) of fuel supply 12.
[0106] In another example color I.D. tag 102 comprises a plurality
of colors, e.g., parallel strips of colors (similar to multi-color
barcode). Color reader 104 is calibrated to scan sequentially
across the color strips, and if the color strips are presented in a
predetermined pattern, then the fuel supply is authenticated.
Alternatively, each color strip may represent a unique piece of
information. For example, a yellow strip may indicate fuel type, a
blue strip may indicate the particular additives included, another
color stripe may indicate the date of manufacture, etc. Processor
18 and color reader 104 may interrogate color I.D. strips/tag 102
to read the information contained on the tag. The colored strips
may be positioned adjacent to each other or may be spaced apart or
separated.
[0107] In another example, color reader 104 does not need to scan
the colored strips, but color reader 104 can take a picture/photo
of the entire strips at once. Digital cameras can be used to
capture an image of the entire color tag and the image is compared
with a stored image to authenticate or processed to determine the
type of fuel supply, as discussed in the previous paragraph. In
this example, the pixels in the captured image can be compared to
the pixels in the stored image to determine whether the captured
image is substantially the same as the stored image. Analog camera
also be used, and the images can be digitized afterward.
[0108] In yet another example, color I.D. tag 102 can have any
pattern, logo, design or graphic that can be captured by color
reader/camera 104 for authentication or processing. Additionally,
tag 102 can be a color hologram, similar to those used in national
currencies worldwide.
[0109] Color I.D. tag 102 can be located on housing 21 of fuel
supply 12, or it can be located within fuel supply 12 similar to
optical sensor 61 behind window 62b, shown in FIG. 1A.
[0110] While it is apparent that the illustrative embodiments of
the invention disclosed herein fulfill the objectives of the
present invention, it is appreciated that numerous modifications
and other embodiments may be devised by those skilled in the art.
For example, the fuel cell may be integrated into load 11. Also,
pump 14 may be eliminated if pressurized fuel supply configurations
are used, such as those described in United States patent
publication no. 2005/0074643, the disclosure of which is
incorporated herein by reference in its entirety. Additionally,
feature(s) and/or element(s) from any embodiment may be used singly
or in combination with feature(s) and/or element(s) from other
embodiment(s). Therefore, it will be understood that the appended
claims are intended to cover all such modifications and
embodiments, which would come within the spirit and scope of the
present invention.
* * * * *
References