METHOD and apparatus for FUEL CELL THERMAL managEmEnt
background
The present invention relates generally to the field of thermal management of fuel
cells and more specifically to the use of fluid heat exchangers for thermal
management of fuel cell stacks.
In a wide variety of applications, fuel cell stacks, such as, for example, solid oxide
fuel cell stacks, have demonstrated a potential for high efficiency and low pollution in
power generation. It is desirable that a fuel cell slack design allow for staging of fuel
cell units and also allow for in-stack fuel reforming . However, problems associated
with thermal management persist, particularly as regards intercooling of the fluid
between a Ifrst fuel cell unit and a second fuel cell unit. Accordingly, opporlunites
exist for improved thermal management of the fuel cell stacks.
SUMMARY
The opportunities described above are addressed, in one embodiment of the present
invention, by a fuel cell assembly comprising a first fuel cell unit adapted for
generating electrical power from a fuel flow and an oxidant flow; and a fluid heat
exchanger adapted for transferring heat between the fuel cell unit and a heat
exchanging fluid flow.
DRAWINGS
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:
figure 1 illustrates an isometric drawing of a fuel cell unit.
figure 2 illustrates an isometric drawing of a fuel cell assembly in accordance with
one embodiment of the present invention.
Figure 3 illustrates an isometric drawing ol'a fule cell assembly in accordance with a
more detailed embodiment of the present invention.
Figure 4 illustrates an isometric drawing of a fuel cell stack.
DETAILED DESCRIPTON
Figure 1 illustrates an isometric drawing of a fuel cell unit showing a fuel flow and an
oxidant flow.
In accordance with one embodiment of the present invention. Figure 2 illustrates an
isometric drawing of a fuel cell assembly 100 comprising a first fuel cell unit 110 and
a fluid heat exchanger 120. In operation, first fuel cell unit 110 generates electrical
power from the fuel (low and the oxidant (low. fluid heal exchanger 120 transfers
heat between fuel cell unit 110 and a heal exchanging fluid flow.
In accordance with another more detailed embodiment of the present invention.
Figure 3 illustrates fuel cell assembly 100 further comprising a second fuel cell unit
130 and an interconnection unit 140. Interconnection unit 140 electrically and
fluidically couples first fuel cell unit 110 to second fuel cell unit 130. According to a
particular embodiment, fluid heat exchanger 120 is disposed inside interconnection
unit 140.
First fuel cell unit 100 and second fuel cell unit 130 comprise any device or system
capable of performing the indicated operations using a fuel cell. Examples of fuel
cells include, without limitation, solid oxide fuel cells, proton exchange membrane
fuel cells, molten carbonate fuel cells, phosphoric acid fuel cells, alkaline fuel cells,
direct methanol fuel cells, regenerative fuel cells, zinc air fuel cells, and protonic
ceramic fuel cells.
In another embodiment of the present invention, first fuel cell unit 110 and second
fuel cell unit 130 comprise at least one planar fuel cell. In still another embodiment
of the present invention, first fuel cell unit 110 and second fuel cell unit 130 comprise
at least one tubular fuel cell.
Figure 4 illustrates an isometric drawing of an exemplary fuel cell stack 150. Fluid
heal exchanger 120 comprises any heat exchanging fluid capable of transferring heat
from first fuel cell unit 110. According to one embodiment, the heat exchanging fluid
and the oxidant are supplied from the same source. In an alternative embodiment, the
heat exchanging fluid flow and the oxidant flow arc supplied from distinct sources.
Examples of heat exchanging fluids include, without limitation, air. steam, oxygen,
hydrogen, water, helium, reformed fuel, unrcformed fuel, and combinations thereof.
Heat transfer from first fuel cell unit 110 and the heat exchanging fluid beneficially
maintains a thermal gradient of fuel cell stack 150 within a predetermined range or
limit. In those embodiments wherein the heal exchanging fluid is unrefbrmed fuel,
the heat transfer additionally serves to reform the fuel for subsequent use in electric
power generation.
In another embodiment, first fuel cell unit 110 and second fuel cell unit 130 have the
fuel flow parallel to the oxidant flow. In an alternative embodiment, the fuel flow is
antiparallel to the oxidant flow. In still another alternative embodiment, as illustrated
in Figure 3 and Figure 4. the fuel flow is orthogonal to the oxidant flow. In
accordance with the embodiment of the present invention illustrated in Figure 3 and
Figure 4. the heat exchanging fluid flow is orthogonal to the fuel flow and the oxidant
flow.
While only certain features of the invention have been illustrated and described
herein, many modification and changes will occur to those skilled in the art. It is.
therefore to be understood that the appended claims are intended lo cover all such
modifications and changes as fall within the true spirit of the invention.
WE CLAIM
1. A fuel cell assembly (100) comprising:
a first fuel cell unit (110) adapted for generating electrical power from a fuel flow and
an oxidant flow; and
a fluid heat exchanger (120) adapted tor transferring heat between said first fuel cell
unit (110) and a heat exchanging fluid flow.
2. The fuel cell assembly (100) of Claim 1 wherein said heat exchanging
fluid flow is orthogonal to said fuel flow and said oxidant flow.
3. The fuel cell assembly (100) of Claim 1 further comprising:
a second fuel cell unit (130): and
an interconnection unit (140) adapted for electrically and fluidically coupling said
first fuel cell unit (110) to said second fuel cell unit (130).
4. The fuel cell assembly (100) of Claim 3. wherein said fluid heat exchanger
(120) is disposed inside said interconnection unit (140).
5. The fuel cell assembly (100) of Claim 1, wherein said heat exchanging
fluid flow and said oxidant flow are supplied from distinct sources.
6. The fuel cell assembly (100) of Claim 1. wherein said heat exchanging
fluid flow comprises a heat exchanging fluid selected from the group consisting of air.
steam. oxygen, hydrogen, helium, water, reformed fuel, unreformed fuel, and
combinations thereof.
7. A fuel cell assembly (100) comprising:
a first fuel cell unit (110) adapted tor generating electrical power from a fuel flow and
an oxidant flow;
a fluid heat exchanger (120) adapted for transferming heat between said first fuel cell
unit (110) and a heat exchange fluid flow said heat exchanging fluid flow being
orthogonal to said fuel flow and said oxidant flow;
a seeond fuel cell unit (130) and
an interconnection unil (140) adapted for electrically and fluidieally coupling said
first fuel eell unit (110) to said second fule cell unit (130)
8. A method comprising:
generating electrical power from a fuel flow and an oxidant flow using a first fuel cell
unit (110): and
transferring heat between said first fuel eell unit ( 110) and a heat exchanging fluid
flow using a fluid beat exehanger (120).
9. The method of claim 8 further comprising:
generating electrical power from said fuel flow and said oxidant flow using a seeond
fuel eell unit (130): and
10. A method comprising:
generating electrical power from a fuel flow and an oxidant flow using a first fuel cell
unit (110): and
transferring heat between said first fuel cell unit (110) and a heat exchanging fluid
flow using a fluid heat exchanger (120). said heal exchanging fluid flow being
orthogonal to said fuel flow and said oxidant flow:
generating electrical power from said fuel flow and said oxidant flow using a second
fuel cell unit (130): and
electrically and fluidically coupling said first fuel cell unit (110) to said second fuel
cell unit (130) using an interconnection unit (140).
Parts List
100 fuel cell assembly
110 first fuel cell unit
120 fluid heat exchanger
130 second fuel cell unit
140 interconnection unit

A fuel cell assembly (100) comprising: a first fuel cell unit (110) adapted for
generating electrical power from a fuel flow and an oxidant flow: and a fluid heat
exchanger (120) adapted for transferring heat between the fuel cell unit (110) and a
heal exchanging fluid flow.