Fuel cell cooling system using a non-dielectric coolant
First Claim
1. In a fuel cell cooling system including a stack comprising a plurality of cells connected electrically in series said stack connected electrically to ground and electrically conductive separator plate means disposed between each pair of adjacent cells, an improvement to said stack comprising:
- at least one of said separator plate means including passageways formed therein parallel to the plane of said plate means;
cooler means for carrying an electrically conductive coolant between said cells and including a plurality of cooler tubes disposed in said passageways and passing through said plate means, said tubes comprising electrically conductive wall means;
a dielectric material disposed between said electrically conductive plate means and said electrically conductive wall means adapted to provide an electrical barrier between said plate means and said wall means and Coolant circulation means in fluid Communication with said cooler means.
0 Assignments
0 Petitions
Accused Products
Abstract
A cooler for removing waste heat from a stack of fuel cells uses a non-dielectric coolant which is carried in a plurality of tubes passing through one or more separator plates in the stack. Preferably the coolant is water so that heat removal is by evaporation of the water within the tubes by boiling. The tubes are electrically insulated from the cells by a coating of dielectric material such as polytetrafluoroethylene. In one embodiment of the present invention the cooler tubes are connected to the stack coolant supply conduits by dielectric hoses having a high length to diameter ratio to provide a several hundred thousand ohm impedance path in case of a flaw in the protective dielectric coating, in order that a short circuit of the stack does not occur.
41 Citations
21 Claims
-
1. In a fuel cell cooling system including a stack comprising a plurality of cells connected electrically in series said stack connected electrically to ground and electrically conductive separator plate means disposed between each pair of adjacent cells, an improvement to said stack comprising:
-
at least one of said separator plate means including passageways formed therein parallel to the plane of said plate means; cooler means for carrying an electrically conductive coolant between said cells and including a plurality of cooler tubes disposed in said passageways and passing through said plate means, said tubes comprising electrically conductive wall means; a dielectric material disposed between said electrically conductive plate means and said electrically conductive wall means adapted to provide an electrical barrier between said plate means and said wall means and Coolant circulation means in fluid Communication with said cooler means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
-
-
11. In a fuel cell cooling system including a stack comprising a plurality of cells connected electrically in series said stack connected electrically to ground and electrically conductive separator plate means disposed between each pair of adjacent cells, an improvement to said system comprising:
-
at least one of said separator plate means including passageways formed therein parallel to the plane of said plate means; cooler means for carrying an electrically conductive coolant between said cells and including a plurality of cooler tubes disposed in said passageways and passing through said plate means, said tubes comprising electrically conductive wall means; a continuous coating of dielectric material disposed on said electrically conductive wall means and having a thickness sufficient to prevent electric current from passing into the coolant to be carried by said tubes; and
a coolant circulation means in fluid communication with said cooler. - View Dependent Claims (12, 13, 14, 15, 16)
-
-
17. A fuel cell power plant cooling system comprising:
-
a non-dielectric coolant; a load; electrical connection means; a plurality of fuel cell stacks connected electrically in series to each other via said electrically connection means and connected electrically in series with said load, said series of stacks being connected electrically to ground, each stack comprising a plurality of cells connected electrically in series and electrically conductive separator plate means disposed between each pair of adjacent cells in each stack, at least one of said separator plate means in each stack including passageways formed therein parallel to the plane of said plate means, each of said stacks including a cooler, said coolant flowing through said cooler, said cooler including cooler tubes disposed within said passageways and passing through said plate means, said tubes comprising electrically conductive wall means, said stack including a dielectric material disposed between said coolant and said plate means; coolant circulation means connected electrically to ground and in fluid communication with each of said coolers; and dielectric conduit means interconnecting said circulation means and said coolers, said conduit means adapted to create a high electrical resistance path through said coolant, said cooler including sacrifical electrode material in contact with said coolant at the higher potential end of said resistance path. - View Dependent Claims (18, 19, 20, 21)
-
Specification