# US 12,763,345 B2 · PEM fuel cell stack > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,763,345 B2 - Document ID: US12763345B2 - Status: Granted - Kind: B2 - Application number: 19/347,351 - Filed: 2025-10-01 - Published: 2026-04-02 - Granted: 2026-10-13 - Earliest claimed: 2024-10-01 - Assignees: Kingsberry Fuel Cell Power, Inc. - Applicants: Kingsberry Fuel Cell Power, Inc. - Inventors: Kingsley Joel Berry - Web page: https://patentgrep.com/patent/US12763345B2 ## CPC - H01M 8/04074: {Heat exchange unit structures specially adapted for fuel cell} - H01M 8/04029: Heat exchange using liquids - H01M 8/04388: {of anode reactants at the inlet or inside the fuel cell} - H01M 8/04708: {of fuel cell reactants} - H01M 8/04753: {of fuel cell reactants} - H01M 8/04768: {of the coolant} - H01M 8/04835: {of fuel cell reactants} - H01M 8/248: Means for compression of the fuel cell stacks - H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY ## Abstract A fuel cell stack comprises two of an interface plate, two or more of an air plate, two or more of a reaction cell, at least one of a fuel-air bipolar plate, and at least one of a fuel-coolant bipolar plate defining a cooling surface. The two of an interface plate, the two or more of an air plate, the two or more of a reaction cell, the at least one of a fuel-air bipolar plate, and the at least one of a fuel-coolant bipolar plate are arranged to provide a reaction cell to cooling surface ratio within the fuel cell stack of from 1:1 to 10:1. ## Claims ### Claim 1 A fuel cell stack having an anode side and a cathode side, the fuel cell stack comprising: two of an interface plate defining a first interface surface, a second interface surface, and a buss slot; two or more of an air plate defining a first air surface and a second surface opposite the first air surface, wherein one of the first air surface or second surface defines a plurality of air channels, and the other, opposite surface is flat; two or more of a reaction cell comprising a membrane electrode assembly disposed between a cathode seal and an anode seal; at least one of a fuel-air bipolar plate having a first fuel-air surface and second fuel-air surface opposite said first fuel-air surface, wherein one of the first or second fuel-air surface defines a plurality of air channels, and the other, opposite surface defines a plurality of fuel channels; and at least one of a fuel-coolant bipolar plate having a cooling surface defining a plurality of cooling channels and a fuel surface defining a plurality of fuel channels opposite the cooling surface, wherein the two of an interface plate, the two or more of an air plate, the two or more of a reaction cell, the at least one of a fuel-air bipolar plate, and the at least one of a fuel-coolant bipolar plate are arranged to provide a reaction cell to cooling surface ratio within the fuel cell stack of from 1:1 to 10:1; wherein the fuel cell stack includes: at least one of a repeating plate sequence having a reaction cell to cooling surface ratio of 2:1 and comprising: (a) the fuel-coolant bipolar plate, (b) one of the reaction cells, (c) the fuel-air bipolar plate, (d) an additional one of the reaction cells, and (e) one of the air plates; and at least one second plate sequence of a plurality of plates having a different reaction cell to cooling surface ratio than the reaction cell to cooling surface ratio of the repeating plate sequence; wherein the fuel cell stack includes one or more instances of the repeating plate sequence disposed within the fuel cell stack; wherein each cooling surface contributing to the reaction cell to cooling surface ratio is defined by a fuel-coolant bipolar plate disposed adjacent a flat surface of one of the air plates; and wherein the repeating plate sequence distributes cooling surfaces within the fuel cell stack relative to active reaction cells to manage temperature distribution across the fuel cell stack. ### Claim 2 (depends on 1) The fuel cell stack as set forth in claim 1, wherein the reaction cell to cooling surface ratio within the fuel cell stack is of from 2:1 to 6:1. ### Claim 3 (depends on 1) The fuel cell stack as set forth in claim 1, wherein the two or more of a reaction cell is further defined as from 30 to 90 of the reaction cell. ### Claim 4 (depends on 3) The fuel cell stack as set forth in claim 3 wherein, the reaction cell has a surface area of from 250 to 650 cm2. ### Claim 5 (depends on 1) The fuel cell stack as set forth in claim 1, wherein: a first compression plate defines a fuel inlet port in fluid communication with an anode side of the fuel cell stack; and a second compression plate defines a fuel outlet port. ### Claim 6 (depends on 5) The fuel cell stack as set forth in claim 5 further comprising: a hydrogen mass flow controller in fluidic communication with the anode side and configured to provide hydrogen at a hydrogen flow rate; and a digital differential pressure regulator in fluidic communication with the fuel inlet port and the fuel outlet port and in electronic communication with the hydrogen mass flow controller; wherein the digital differential pressure regulator senses a pressure differential between the fuel inlet port and the fuel outlet port on the anode side and adjusts the hydrogen flow rate to maintain a target pressure differential to improve fuel usage efficiency independent of a current load of the fuel cell stack. ### Claim 7 (depends on 1) The fuel cell stack as set forth in claim 1 having a plurality of pressurization channels disposed about a perimeter of the fuel cell stack and a plurality of dynamic fasteners disposed in the plurality of pressurization channels, each dynamic fastener comprising a tie rod having a first and a second end, at least one of a mount, a biasing element, and an endpiece. ### Claim 8 (depends on 7) The fuel cell stack as set forth in claim 7, wherein each of the plurality of dynamic fasteners comprise: a first mount, a first biasing element, and a first endpiece configured for engagement with the first end; and a second mount, a second biasing element, and a second endpiece configured for engagement with the second end. ### Claim 9 (depends on 8) The fuel cell stack as set forth in claim 8, wherein a surface pressure of from 80 to 120 psi is maintained evenly across the two or more of the reaction cell, independent of the number of the two or more of the reaction cell in the fuel cell stack. ### Claim 10 (depends on 7) The fuel cell stack as set forth in claim 7, wherein the plurality of pressurization channels is further defined as from 6 to 17 channels and the plurality of dynamic fasteners is further defined as from 6 to 17. ### Claim 11 (depends on 7) The fuel cell stack as set forth in claim 7, wherein: the plurality of dynamic fasteners provide a compression displacement of a length of the fuel cell stack of from 6 to 16 mm; and/or each of the plurality of dynamic fasteners have the same force-deflection relationship or force-displacement curve. ### Claim 12 (depends on 7) The fuel cell stack as set forth in claim 7, wherein a surface pressure of 80 to 120 psi is maintained on the two or more of a reaction cell. ### Claim 13 (depends on 1) The fuel cell stack as set forth in claim 1, wherein the plurality of cooling channels includes from 4 to 26 cooling channels. ### Claim 14 (depends on 13) The fuel cell stack as set forth in claim 13, wherein at least two of the cooling channels share a cooling input port and a cooling output port. ### Claim 15 (depends on 14) The fuel cell stack as set forth in claim 14, wherein a cooling input port to cooling channel ratio is from 1:1 to 1:4. ### Claim 16 (depends on 14) The fuel cell stack as set forth in claim 14, wherein a cooling input port to cooling channel ratio is from 1:2 to 1:3. ### Claim 17 (depends on 13) The fuel cell stack as set forth in claim 13, wherein at least a portion of the cooling channels have: an average width of from 0.75 to 3.25 mm; and/or an average channel depth of from 0.3 to 1.5 mm. ### Claim 18 (depends on 17) The fuel cell stack as set forth in claim 17, wherein each of the cooling channels is partially defined by a cooling interface surface proximal the reaction cell, and a cooling interface surface to channel depth ratio is from 2:1 to 1:2. ### Claim 19 (depends on 13) The fuel cell stack as set forth in claim 13, wherein the plurality of cooling channels has a serpentine pattern. ### Claim 20 (depends on 19) The fuel cell stack as set forth in claim 19, wherein each of the plurality of cooling channels have from 3 to 12 180° turns. ### Claim 21 (depends on 1) The fuel cell stack as set forth in claim 1, further comprising a passive water management membrane, wherein: cooling water circulated through the plurality of cooling channels defined by the cooling surface; and/or an exhaust mixture of water and air from the cathode side of the fuel cell stack, penetrates the passive water management membrane to humidify hydrogen fuel supply of the anode side of the fuel cell stack. ### Claim 22 (depends on 21) The fuel cell stack as set forth in claim 21, wherein the passive water management membrane comprises a sulfonated tetrafluoroethylene-based fluoropolymer-copolymer having a thickness of from 40 to 60 mm. ### Claim 23 (depends on 21) The fuel cell stack as set forth in claim 21, wherein the passive water management membrane is located between a cathode exhaust flow passageway and a hydrogen supply passageway. ### Claim 24 (depends on 1) A method of assembling a fuel cell stack as set forth in claim 1, said method comprising the steps of: arranging the two of an interface plate, the two or more of an air plate, the two or more of a reaction cell, the at least one of a fuel-air bipolar plate, and the at least one of a fuel-coolant bipolar plate to create a reaction cell to cooling surface ratio within the fuel cell stack of from 2:1 to 6:1; and tightening a plurality of dynamic fasteners to activate a plurality of biasing elements and provide a compression displacement of a length of the fuel cell stack of from 6 to 16 mm. ### Claim 25 (depends on 1) A method of generating power with the fuel cell stack of claim 1 having an anode side and a cathode side and comprising a hydrogen mass flow controller in fluidic communication with a fuel inlet port on the anode side and a digital differential pressure regulator in fluidic communication with the fuel inlet port and a fuel outlet port on the anode side and in electronic communication with the hydrogen mass flow controller, said method comprising the steps of: providing a hydrogen feed stream to the anode side of the fuel cell stack at a hydrogen flow rate; determining a pressure differential between the fuel inlet port and the fuel outlet port with the digital differential pressure regulator; and adjusting the hydrogen flow rate with the hydrogen mass flow controller to achieve a target pressure differential. ### Claim 26 (depends on 25) The method of generating power set forth in claim 25, wherein the steps of determining and adjusting are conducted a frequency of greater than once per second. ### Claim 27 (depends on 1) A method of humidifying a hydrogen feed stream while generating power with the fuel cell stack of claim 1 having an anode side and a cathode side and comprising two of an interface plate, two or more of an air plate, two or more of a reaction cell, at least one of a fuel-air bipolar plate, at least one of a fuel-coolant bipolar plate, and a passive water management membrane comprising a sulfonated tetrafluoroethylene-based fluoropolymer-copolymer, the method comprising: supplying a hydrogen feed stream to the anode side of the fuel cell stack and oxygen to the cathode side of the fuel cell stack; contacting the hydrogen feed stream with the passive water management membrane; supplying water to a coolant flow path defined by the fuel cell stack; cooling the two or more of a reaction cell with the water flowing in the coolant flow path; contacting the passive water management membrane with the water used in the step of cooling and/or exhaust water from the two or more of a reaction cell; and humidifying the hydrogen feed stream via back diffusion through the passive water management membrane.