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US 2007/0178347 A1Published application
Coolant bypass for fuel cell stack
OwnerJames Siepierski, Martin Hoch +2inventors
InventorsJames Siepierski, Martin Hoch, Matthew Beutel, Lee Whitehead
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Abstract
A heat regulating system for an electrochemical conversion assembly. In one embodiment, the electrochemical conversion assembly is a fuel cell, and the device includes one or more fluid-manipulating components to vary the amount of a coolant or related heat regulating fluid used to maintain a preferred temperature in the fuel cell. Preferred fuel cell operating temperatures can be more easily achieved by selectively bypassing a portion of the coolant around the fuel cell during certain temperature or power demand regimes. A controller can be used to monitor and selectively vary the extent to which at least one of these components modifies the flow of fluid past the fuel cell.
Claims22
A fuel cell assembly comprising:
- at least one fuel cell comprising:
- an anode configured to accept a first reactant therein;
- a cathode configured to accept a second reactant therein;
- a membrane disposed between said anode and cathode, said membrane configured to allow an ionized portion of said first reactant to pass therethrough on its way from said anode to said cathode;
- a fluid conveying circuit cooperative with said at least one fuel cell, said circuit comprising:
- a temperature-regulating flowpath configured to convey a first portion of a fluid flowing in said circuit past said at least one fuel cell such that said first portion is in thermal communication therewith;
- a bypass flowpath fluidly parallel to said temperature-regulating flowpath and configured to selectively convey a second portion of said fluid around said at least one fuel cell such that said second portion is substantially thermally decoupled therefrom, wherein the ratio of flow of said first and second portions is a function of at least one of an ambient temperature, a temperature within said fuel cell and a load demand on said fuel cell;
- and
- at least one device for promoting the circulation of said first and second portions through said circuit.
6 more elements
An electrochemical conversion assembly comprising:
- a plurality of anodes each configured to transport a first reactant therethrough;
- a plurality of cathodes each configured to transport a second reactant therethrough;
- a membrane electrode assembly disposed between each of said anodes and cathodes such that together said anodes, cathodes and membranes define a stack;
- and
- a coolant system configured to regulate the temperature produced in said assembly by a reaction between said first and second reactants, said coolant system comprising:
- a coolant inlet manifold configured to deliver at least a portion of a coolant between said anodes and cathodes;
- a coolant outlet manifold configured to receive at least a portion of said coolant between said anodes and cathodes, said fluid outlet manifold in fluid communication with said coolant inlet manifold;
- a coolant flowpath configured to regulate a temperature within said stack, said coolant flowpath comprising:
- a temperature-regulating flowpath configured to convey a first portion of said coolant past said stack such that said first portion is in thermal communication therewith;
- and
- a bypass flowpath fluidly parallel to said temperature-regulating flowpath and configured to selectively convey a second portion of said coolant around said stack such that said second portion is substantially thermally decoupled therefrom, wherein the division of flow between said first and second portions is a function of at least one of an ambient temperature, a temperature within said stack and a load demand on said stack;
- a pump fluidly coupled to said coolant flowpath to circulate said coolant therethrough;
- at least one valve disposed in said bypass flowpath to permit said selective conveyance of said second portion therethrough;
- and
- a controller cooperative with said pump and said valve such that upon attainment of at least one of a predetermined temperature or load condition, said controller actuates at least one of said valve or said pump to effect said selective conveyance of said second portion through said bypass flowpath.
12 more elements
A method of operating a fuel cell system, said method comprising:
- configuring at least one fuel cell to comprise an anode, a cathode, an electrolyte disposed between said anode and said cathode, and a heat regulating circuit configured to flow a heat regulating fluid through said fuel cell, said circuit comprising:
- conduit defining a common flowpath, a coolant flowpath and a bypass flowpath;
- and
- at least one flow regulating device disposed in said conduit;
- sensing a parameter corresponding to at least one of an ambient temperature, a temperature within said at least one fuel cell or a load on at least one said fuel cell;
- manipulating said at least one flow regulating device upon attainment of a threshold value from said sensed parameter;
- and
- introducing a reductant into said anode and an oxidant into said cathode so that said fuel cell produces electricity.
5 more elements
Dependencies are inferred from the claim text.