# US 5,346,661 A · Hot compression process for making edge seals for fuel cells > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,346,661 A - Document ID: US5346661A - Status: Granted - Kind: A - Application number: 07/842,765 - Filed: 1992-03-02 - Granted: 1994-09-13 - Earliest claimed: 1990-05-14 - Assignees: The United States of America as represented by the Department of Energy - Inventors: Thomas J. Dunyak; Samuel J. Granata, Jr. - Web page: https://patentgrep.com/patent/US5346661A ## CPC - H01M 8/0271: Sealing or supporting means around electrodes, matrices or membranes - B29C 67/0044: {for shaping edges or extremities (B29C57/00 takes precedence)} - B29C 70/763: {the edges being disposed in a substantial flat plane} - B29C 33/62: based on polymers or oligomers - B29C 43/00: Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor {(by liberation of internal stresses B29C61/006)} - B29K 2021/00: Use of unspecified rubbers as moulding material - B29L 2031/3468: {Batteries, accumulators or fuel cells (battery cases B29L2031/7146)} - Y02E 60/50: Fuel cells - Y02P 70/50: Manufacturing or production processes characterised by the final manufactured product - H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY - B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00) - B29K: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR {MOULDS, } REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS - B29L: INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION - Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS ## Abstract A hot compression process for forming integral edge seals in anode and cade assemblies wherein the assemblies are made to a nominal size larger than a finished size, beads of AFLAS are applied to a band adjacent the peripheral margins on both sides of the assemblies, the assemblies are placed in a hot press and compressed for about five minutes with a force sufficient to permeate the peripheral margins with the AFLAS, cooled and cut to finished size. ## Claims ### Claim 1 A hot compression process for making edge seals for fuel cells, comprised of pairs of electrode assemblies with a matrix seal disposed between the electrodes of each pair, each pair of assemblies disposed between two gas-conducting plates comprising the steps of: forming a rectangular-shaped electrode assembly to a nominal size larger than a finished size, the assembly having opposed sides, one side for contacting a gas-conducting plate and the opposed side for conducting a matrix seal; applying at least one bead of elastomer to a peripheral band adjacent the peripheral margins on each opposed side of the electrode assembly so that the beads on the opposing sides are aligned; providing a pair of press platens; heating the press platens to a temperature generally in the range of 180.degree. C. to 230.degree. C.; compressing the electrode assembly with the elastomer applied thereto between the heated press platens for a sufficient period and with a force sufficient to cause the beads to permeate the entire thickness of the adjacent assembly so that there is essentially no buildup of the elastomer between the platen and the electrode assembly and the elastomer forms a generally gas impervious seal adjacent the peripheral margins, the seal extending from one opposed side of the assembly to the other for preventing gas leakage across the peripheral margins for the assembly; removing the electrode assembly from between the platens; allowing the removed electrode assembly to cool to ambient temperature; and trimming the cooled electrode assembly to a finished size. ### Claim 2 (depends on 1) The process of claim 1, wherein the step of applying the elastomer to the peripheral bands of the electrode assembly comprises applying two beads of elastomer to both sides of the electrode assembly, wherein the beads on opposite sides are aligned. ### Claim 3 (depends on 2) The process of claim 2, wherein the elastomer beads are applied in the form of a liquid solution. ### Claim 4 (depends on 3) The process of claim 3, wherein the step of applying the elastomer in the form of a liquid solution comprises applying a solution, which is about 22% by weight AFLAS. ### Claim 5 (depends on 4) The process of claim 4, wherein the liquid solution is applied by an automatic dispenser. ### Claim 6 (depends on 5) The process of claim 5, wherein the elastomer is AFLAS. ### Claim 7 (depends on 4) The process of claim 4, and further comprising the step of allowing the electrode assembly with the elastomer applied in liquid form to air dry at ambient temperature for about 1 hour. ### Claim 8 (depends on 7) The process of claim 7 and further comprising the steps of placing the air-dried electrode assembly in an oven, wherein the temperature is maintained at about 130.degree. C. and keeping the electrode assembly in the oven for about 10 minutes. ### Claim 9 (depends on 1) The process of claim 1, wherein the electrode assembly comprises a sheet of backing paper with a catalyst layer centrally disposed on the backing paper and filler strips of generally the same thickness as the catalyst layer abutting the catalyst and tacked to the backing paper with the elastomer. ### Claim 10 (depends on 9) The process of claim 9, wherein the electrode assembly is made up of a layer of silicon carbide disposed over the catalyst layer and within the filler strips generally being as thick as the combined thickness of the catalyst and insulating layers. ### Claim 11 (depends on 1) The process of claim 1, wherein the pressure is applied to the press platens for a period of about 5 minutes. ### Claim 12 (depends on 11) The process of claim 11, wherein the press platens apply the pressure only on the peripheral strips adjacent the peripheral margins of the electrode assemblies. ### Claim 13 (depends on 1) The process of claim 1, including the additional step of: providing a means between the press platens and the elastomer beads on the sides of the electrode assembly for preventing sticking of the elastomer to the platens in a temperature range of 180.degree. C. to 230.degree. C. before the press platens are heated to a temperature generally in the range of 180.degree. C. to 230.degree. C. ### Claim 14 (depends on 1) The process of claim 1, including the additional step of: providing a fluorocarbon resin between the press platens and the elastomer beads on the sides of the electrode assembly for preventing sticking of the elastomer to the platens in a temperature range of 180.degree. C. to 230.degree. C. before the press platens are heated to a temperature generally in the range of 180.degree. C. to 230.degree. C.